Unprotected Group Research Articles

Protection of side-branch ostium by the jailed balloon technique validated by three-dimensional optical coherence tomography

Objective: To evaluate the protective effect of jailed balloon technique on side branch (SB) ostium using three-dimensional optical coherence tomography(OCT). Methods: This is a retrospective study. Consecutive coronary disease patients with coronary artery bifurcation lesions who underwent percutaneous coronary intervention (PCI) and completed pre-and post-procedural OCT examinations at the Chinese People's Liberation Army General Hospital from September 2019 to March 2022 were enrolled. Patients were divided into the jailed balloon technique group and the unprotected group according to the options applied for the SB. The SB ostium area difference was calculated from OCT images (SB ostium area difference=post-PCI SB ostium area-pre-PCI SB ostium area). The SB ostium area differences were compared between the two groups and compared further in the subgroup of true bifurcation lesions and non-true bifurcation lesions. In the jailed balloon group, the SB ostium area difference was compared between the active jailed balloon technique and the conventional jailed balloon technique, between the jailed balloon>2.0 mm diameter and the jailed balloon≤2.0 mm diameter, and between the higher balloon pressure (>4 atm, 1 atm=101.325 kPa) and the lower balloon pressure (≤4 atm). Multivariate linear regression analysis was used to explore the correlation between the technical parameters of the jailed balloon technique and the SB protection effect. Results: A total of 176 patients with 236 bifurcation lesions were enrolled, aged (60.7±9.3) years, and there were 128 male patients (72.7%). There were 67 patients in the jailed balloon technique group with 71 bifurcation lesions and 123 patients in the unprotected group with 165 bifurcation lesions. Fourteen patients had 2 to 3 lesions, which were treated in different ways, so they appeared in the unprotected group and the jailed balloon technique group at the same time. The area difference in SB ostium was greater in the jailed balloon group than in the unprotected group (0.07 (-0.43, 1.05)mm2 vs.-0.33 (-0.83, 0.26)mm2, P<0.001), and the results were consistent in the true bifurcation lesion subgroup (0.29 (-0.35, 0.96)mm2 vs.-0.26 (-0.64, 0.29)mm2, P=0.004), while the difference between the two groups in the non-true bifurcation lesion subgroup was not statistically significant (P=0.136). In the jailed balloon technique group, the SB ostium area difference was greater in patients treated with the active jailed balloon technique than in those treated with the conventional jailed balloon technique ((0.43±1.36)mm2 vs. (-0.22±0.52)mm2, P=0.013). The difference in SB ostium area was greater in those using>2.0 mm diameter jailed balloons than in those using≤2.0 mm diameter jailed balloons (0.25 (-0.51, 1.31) mm2 vs.-0.01 (-0.45, 0.63) mm2, P=0.020), while SB ostium area difference was similar between those endowed with higher balloon pressure (>4 atm) compared to those with lower balloon pressure (≤4 atm) (P=0.731). Multivariate linear regression analysis showed that there was a positive correlation between jailed balloon diameter and SB ostium area difference (r=0.344, P=0.019). Conclusions: The jailed balloon technique significantly protects SB ostium, especially in patients with true bifurcation lesions. The active jailed balloon technique and larger diameter balloons may provide more protection to the SB.

Catalytic Asymmetric Hydroalkoxylation and Formal Hydration and Hydroaminoxylation of Conjugated Dienes.

The straightforward construction of stereogenic centers bearing unprotected functional groups, as in nature, has been a persistent pursuit in synthetic chemistry. Abundant applications of free enantioenriched allyl alcohol and allyl hydroxylamine motifs have made the asymmetric hydration and hydroaminoxylation of conjugated dienes from water and hydroxylamine, respectively, intriguing and efficient routes that have, however, been unachievable thus far. A fundamental challenge is the failure to realize transition-metal-catalyzed enantioselective C-O bond constructions via hydrofunctionalization of conjugated dienes. Here, we perform a comprehensive study toward the stereoselective formal hydration and hydroaminoxylation of conjugated dienes by synthesizing a set of new P,N-ligands and identifying an aryl-derived oxime as a surrogate for both water and hydroxylamine. Asymmetric hydroalkoxylation with new P,N-ligands is also elucidated. Furthermore, versatile derivatizations following hydration provide indirect but concise routes to formal hydrophenoxylation, hydrofluoroalkoxylation, and hydrocarboxylation of conjugated dienes that have been unreported thus far. Finally, a ligand-to-ligand hydrogen transfer process is proposed based on the results of preliminary mechanistic experiments.

Integration of Ultrastructural and Computational Approaches Reveals the Protective Effect of Astaxanthin against BPA-Induced Nephrotoxicity.

Bisphenol A (BPA) is an environmental contaminant that can induce deleterious organ effects. Human Cytochrome P450 CYP2C9 enzyme belongs to the essential xenobiotic-metabolizing enzymes, producing ROS as a byproduct. Astaxanthin (ATX) is a powerful antioxidant that protects organs and tissues from the damaging effects of oxidative stress caused by various diseases. This study investigated the possible protective impacts of ATX against BPA-induced nephrotoxicity and its underlying mechanism. Kidney tissues were isolated and examined microscopically from control, protected, and unprotected groups of rats to examine the potential protective effect of ATX against nephrotoxicity. Moreover, a molecular dynamic (MD) simulation was conducted to predict the performance of ATX upon binding to the active site of P450 CYP2C9 protein receptor as a potential mechanism of ATX protective effect. Implemented computational methods revealed the possible underlying mechanism of ATX protection; the protective impact of ATX is mediated by inhibiting P450 CYP2C9 through binding to its dimeric state where the RMSF value for apo-protein and ATX-complex system were 5.720.57 and 1.040.41, respectively, implicating the ATX-complex system to have lesser variance in its residues, leading to the prevention of ROS excess production, maintaining the oxidant-antioxidant balance and re-establishing the proper mitochondrial functionality. Furthermore, the experimental methods validated in silico outcomes and revealed that ATX therapy effectively restored the typical histological architecture of pathological kidney tissues. ATX prevents BPA-induced nephrotoxicity by controlling oxidative imbalance and reversing mitochondrial dysfunction. These outcomes shed new light on the appropriate use of ATX as a treatment or prophylactic agent for these severe conditions.

Structure-Activity Relationship Study of N-Hydroxyphtalimide Derivatives for the Detection of Amines during Fmoc-Solid-Phase Peptide Synthesis.

Previously, we developed a method for the detection of unprotected amino groups based on their reversible reaction with N-hydroxyphthalimide (NHPI) to form intensely colored products, which can be useful when conducting solid-phase peptide synthesis. Here, we describe a structure-activity relationship study of NHPI derivatives to identify the derivative best suited for this method using a spectrophotometer toward the estimation of chemical yields. We found that the products resulting from the reaction of the derivative with an unprotected amino group were only intensely colored if the structure of the derivative incorporated an NHPI framework. We also prepared five peptides, including those containing N-methyl and D-amino acid, and Pro residues, using our reversible detection method to detect unprotected amino groups. The mechanism of the detection reaction was also studied by the structural analysis of the NHPI (1) and diisopropylamine complex and concluded to entail salt formation between the N-hydroxy group and amine.

Seroprevalence of SARS-CoV-2 Among Children Visiting a Tertiary Hospital in Himachal Pradesh, India

Introduction: Research on Coronavirus Disease-2019 (COVID19) seroprevalence in children and adolescent population across the globe is quite limited. In India, there is a dearth of data on COVID-19 seropositivity, especially in unvaccinated paediatric population, particularly in the Himalayan region. Aim: To estimate the seroprevalence of COVID-19 in children presenting in a tertiary care health institution. Materials and Methods: A hospital-based cross-sectional serosurvey was conducted on 500 children, from October 2021 to March 2022 in paediatric age group, attending Indira Gandhi Medical College Shimla, Himachal Pradesh, India, for various health related concerns such as fever, cough, loose stools, vomiting and fast breathing using convenience sampling. Socio-demographic profile was recorded and blood sample was drawn for COVID-19 antibody titre estimation. Chi-squared and Fisher’s-exact tests for proportions was used for testing statistical significance. Results: A total of 500 children, age ranged from 12 hours to 17 years 7 months were enrolled with maximum children belonging to 01-05 years age group and there was slight male preponderance. Seropositivity in males (27.3%) was significantly higher than females (8.3%). Highest (42.3%) seropositivity was seen in age group of 06 months to 01 year. About 10.8% of cases were positive for Immunoglobulin (Ig) G antibody, 4.4% were positive for IgM antibody, while about 6.6% cases were positive for both antibodies. Conclusion: The seroprevalence status of children and adolescents is quite low in this region, revealing the high susceptibility of children to SARS-CoV-2 in the study region. It further emphasises benefits of serological testing in children for SARS-CoV-2 as well as the need of safe and effective vaccination for the unimmunised, unprotected and vulnerable paediatric age group.

Unprotected amine transfer performed by non-heme iron(II) complexes.

Direct amination of C-H or CC bonds using unprotected amino groups is very challenging, especially with earth abundant metal ions. Here we show that a bioinspired iron(II) complex catalyses the double amination of its dangling benzyl branch in the presence of hydroxylamine derivatives as the unprotected amine donor and that the replacement of the benzyl branch by a methyl group also allows the aziridination of styrene.

Evaluating the effect of the protector cap for castable implant abutments on reverse tightening values

Statement of problemScrew loosening is the most common mechanical complication with implant prostheses. How the alteration of implant-to-abutment connection surfaces that occurs during laboratory procedures affects screw loosening is unclear. PurposeThe purpose of this in vitro study was to compare the reverse tightening value (RTV) differences between custom castable abutments before casting, after casting in a conventional manner, and after casting with custom protector caps and pegs. Material and methodsThirty implants with a standard-diameter conical connection (NobelReplace Conical Connection 4.3×13 mm; Nobel Biocare AG) and 30 premachined 4.3-mm GoldAdapt abutments (GoldAdapt; Nobel Biocare AG) were selected for this study. Specimens were divided into 3 groups (n=10): the uncast custom castable abutment group (UCCA) in which abutments were new and not cast; the unprotected custom castable abutment group (UPCCA) in which abutments were cast and devested with airborne-particle abrasion; and the protected custom castable abutment group (PCCA) in which abutments were cast by using protector caps and pegs made by milling zirconia and then devested with airborne-particle abrasion. All abutments in each group were tightened to 35 Ncm with a calibrated digital tightening device. After 10 minutes, all screws were retightened to 35 Ncm. At 3 hours, each screw was loosened, and the value at which the initial loosening occurred was documented as the RTV. The results were statistically analyzed with 1-way ANOVA to explore differences, and post hoc tests with Tukey adjustment were used for multiple comparisons. ResultsAmong the tested groups, the mean RTV ranged from 19.89 Ncm to 27.19 Ncm: UCCA 27.19 Ncm, UPCCA 19.89 Ncm, and PCCA 24.24 Ncm. A significant difference was found among the tested groups (P<.05). ConclusionsCasting procedures, especially devestment with airborne-particle abrasion, affected implant-abutment connections and the seat site of the screw. Protecting the implant connection site and the seat site of the abutment screw with protector caps and pegs prevented a significant loss of the RTV.

The Role and Importance of the Prosecutor's Office in Protecting the Rights of Persons with Disabilities

This scientific work reveals the importance of the activities of the Prosecutors Office of the Russian Federation in the protection of a socially unprotected group of persons such as the disabled. To date, an extensive domestic and international regulatory framework has been developed that regulates the protection of the rights of persons with disabilities. However, relevant offenses continue to be identified. In view of this, the employees of the Prosecutors Office of the Russian Federation are taking a number of effective measures to restore these rights, including going to court with a statement in defense of the rights, freedoms, and legitimate interests of an indefinite number of persons. Relying on its activities on the principle of publicity, the Prosecutors Office is taking the first significant steps in protecting the rights of persons with disabilities.

Iron-Catalyzed Cross-Electrophile Coupling of Inert C–O Bonds with Alkyl Bromides

Iron-Catalyzed Cross-Electrophile Coupling of Inert C–O Bonds with Alkyl Bromides

Zygo-Albuside A: New Saponin from Zygophyllum album L. with Significant Antioxidant, Anti-Inflammatory and Antiapoptotic Effects against Methotrexate-Induced Testicular Damage.

Chemical investigation of the crude extract of the aerial part of Zygophyllum album L. (Z. album) led to the isolation of a new saponin, Zygo-albuside A (7), together with seven known compounds, one of them (caffeic acid, compound 4) is reported in the genus for the first time. NMR (1D and 2D) and mass spectrometric analysis, including high-resolution mass spectrometry (HRMS), were utilized to set up the chemical structures of these compounds. The present biological study aimed to investigate the protective antioxidant, anti-inflammatory, and antiapoptotic activities of the crude extract from the aerial part of Z. album and two of its isolated compounds, rutin and the new saponin zygo-albuside A, against methotrexate (MTX)-induced testicular injury, considering the role of miRNA-29a. In all groups except for the normal control group, which received a mixture of distilled water and DMSO (2:1) as vehicle orally every day for ten days, testicular damage was induced on the fifth day by intraperitoneal administration of MTX at a single dose of 20 mg/kg. Histopathological examination showed that pre-treatment with the crude extract of Z. album, zygo-albuside A, or rutin reversed the testicular damage induced by MTX. In addition, biochemical analysis in the protected groups showed a decrease in malondialdehyde (MDA), interleukin-6 (IL-6) and IL-1β, Bcl-2-associated-protein (Bax), and an increase in B-cell lymphoma 2 (Bcl-2) protein, catalase (CAT), superoxide dismutase (SOD) in the testis, along with an increase in serum testosterone levels compared with the unprotected (positive control) group. The mRNA expression levels of nuclear factor-kappa B (NF-κB), tumor necrosis factor-α (TNF-α), p53, and miRNA-29a were downregulated in the testicular tissues of the protected groups compared with the unprotected group. In conclusion, the study provides sufficient evidence that Z. album extract, and its isolated compounds, zygo-albuside A and rutin, could alleviate testicular damage caused by the chemotherapeutic agent MTX.

Features of psychosocial work with adolescents subjected to violence

The modern society of the Russian Federation has been affected by serious transformations in various spheres of life: economic, political, pedagogical, psychological, as well as social one. These changes have led to a number of negative consequences, such as a decrease in the standard of living of the majority of the population, stratification in terms of financial situation, and lack of confidence in the future. These factors have seriously influenced the growth of aggression in society and domestic violence, from which children suffer primarily. Children are the most vulnerable and unprotected social group, therefore, the increase in violence is not only a federal but also a global issue. Violence against children in the family is a significant problem of today's modern society, so its relevance is rapidly increasing. As a rule, any violent action on the part of family members radically changes the life of a child or adolescent for the worse. Very often, the causes of violent acts are low income, alcohol or drug addiction of family members, lack of love for the child, as well as mental and physiological fatigue. Unfortunately, it is quite common that children who have been abused by their parents begin to perceive violence as a means of solving problems and the norm of communication, therefore, the number of juvenile crimes is growing. After analyzing the statistics, it can be seen that about 2 million children and adolescents under the age of 16 become victims of violent acts by their own parents annually, and more than 50 thousand children and adolescents run away from home for the sake of salvation. According to statistics, 10 % of abused children die, while the rest have serious disorders in the physiological and psycho-emotional spheres of life.

Gauging the impact of a pandemic on the lives and livelihoods of female domestic worker across Indian cities

Domestic workers are one of the most unprotected groups of the global workforce in informal employment who remain outside the ambit of social security and legal protection. Despite their significant contribution to the economy and society, they are often invisible and undervalued. The pre-existing adversities and vulnerabilities became all the more evident during the recent health crisis. While different groups of workers faced constraints to support their livelihood, the women domestic workers were hardest hit, facing total or near unemployment, job losses and economic distress. This paper attempts to analyse the impact of pandemic on the lives and livelihoods of female domestic workers in five Indian cities including Pune, Lucknow, Jhansi, Katni and Bhopal. The analytical findings from the random sample survey of 250 female domestic worker provides a temporal analysis of the impact of covid-19 on the nature of work, income, expenditure and consumption across the various cities of India. Our findings not only increase our understanding on the impact of the crisis for domestic worker but also informal workers in general.

Cравнительная оценка рисков инфицирования sars-cov-2 у работников медицинских организаций крупного промышленного города в период пандемии

The COVID-19 pandemic has produced its effects on functioning of all the state institutions, the public healthcare system being a peculiar one among them. Medical personnel have become an unprotected population group that was actively involved into the epidemic process. Results produced by several studies indicate that relative risks to become infected with COVID-19 are by up to 11.6 times higher for medical personnel than in population at large. A share of medical personnel among patients with COVID-19 varies in different countries, from 4.2 % in China to 17.8 % in the USA. According to official statistics, in 2020 a share of medical personnel who became infected with COVID-19 in in-hospital foci amounted to 68.6 % in the RF regions located in the Urals and Siberian Federal Districts. High epidemic potential of the virus and intensive mass contacts between medical personnel and their patients make for rapid SARS-CoV-2 spread and infection among them. It is vital to examine all the range of risk factors that cause SARS-CoV-2 infection among medical personnel. The present study involved using “The map of epidemiological investigation focused on the incidence of the new coronavirus infection (COVID-19) in medical personnel”. The map was located on Google Cloud Platform. Overall, 613 medical workers from different medical organizations took part in the research. We applied sociological, epidemiological and statistical research techniques. We established that work in an infectious diseases hospital increased a relative risk of SARS-CoV-2 infection by 1.8 times (RR = 1.78; 95 % CI [1.65–1.93]). The total risk of SARS-CoV-2 infection was insignificant for workers employed at a medical organization that provided scheduled medical assistance to population (RR = 1.02; 95 % CI [1.00–1.04]). However, certain factors created elevated risks of infection. Any contacts with COVID-19 patients who were close relatives, friends or neighbors were established to be significant (RR = 1.13; 95 % CI [1.04–1.228]). The research results should be used when organizing work procedures and anti-epidemic activities in infectious diseases hospitals and medical organizations providing scheduled assistance to population. The focus should be on providing medical personnel with personal protective equipment as well as on calculating relevant duration of a work shift relying on the risk-based approach.

Risks of becoming infected with SARS-CoV-2 for medical personnel in a large industrial city during the pandemic: comparative assessment

The COVID-19 pandemic has produced its effects on functioning of all the state institutions, the public healthcare system being a peculiar one among them. Medical personnel have become an unprotected population group that was actively involved into the epidemic process. Results produced by several studies indicate that relative risks to become infected with COVID-19 are by up to 11.6 times higher for medical personnel than in population at large. A share of medical personnel among patients with COVID-19 varies in different countries, from 4.2 % in China to 17.8 % in the USA. According to official statistics, in 2020 a share of medical personnel who became infected with COVID-19 in in-hospital foci amounted to 68.6 % in the RF regions located in the Urals and Siberian Federal Districts. High epidemic potential of the virus and intensive mass contacts between medical personnel and their patients make for rapid SARS-CoV-2 spread and infection among them. It is vital to examine all the range of risk factors that cause SARS-CoV-2 infection among medical personnel. The present study involved using “The map of epidemiological investigation focused on the incidence of the new coronavirus infection (COVID-19) in medical personnel”. The map was located on Google Cloud Platform. Overall, 613 medical workers from different medical organizations took part in the research. We applied sociological, epidemiological and statistical research techniques. We established that work in an infectious diseases hospital increased a relative risk of SARS-CoV-2 infection by 1.8 times (RR = 1.78; 95 % CI [1.65–1.93]). The total risk of SARS-CoV-2 infection was insignificant for workers employed at a medical organization that provided scheduled medical assistance to population (RR = 1.02; 95 % CI [1.00–1.04]). However, certain factors created elevated risks of infection. Any contacts with COVID-19 patients who were close relatives, friends or neighbors were established to be significant (RR = 1.13; 95 % CI [1.04–1.228]). The research results should be used when organizing work procedures and anti-epidemic activities in infectious diseases hospitals and medical organizations providing scheduled assistance to population. The focus should be on providing medical personnel with personal protective equipment as well as on calculating relevant duration of a work shift relying on the risk-based approach.

Controllable Polymerization of N -Substituted β-Alanine N -Thiocarboxyanhydrides for Convenient Synthesis of Functional Poly(β-peptoid)s

Controllable Polymerization of <i>N</i> -Substituted β-Alanine <i>N</i> -Thiocarboxyanhydrides for Convenient Synthesis of Functional Poly(β-peptoid)s

Bioethics in an era of change: unprotected groups

The article deals with such a phenomenon as the reorientation of bioethics in the era of change. Attention is focused on the fact that the COVID19 pandemic has exposed new problems in practical medicine. Special attention should now be paid to the vulnerable groups that have been most affected by the pandemic children and the elderly. At the same time, the author disagrees with the unification of gerontology and geriatrics into one, exclusively medical, scientific specialty in the list of the Higher Attestation Commission of 2022. The idea is expressed that bioethics can and should act as a phenomenon synthesizing all aspects of the accompaniment of old age. The author calls for the development of this direction, including on the pages of this magazine.

Highly Stereoselective, Organocatalytic Mannich-type Addition of Glyoxylate Cyanohydrin: A Versatile Building Block for the Asymmetric Synthesis of β-Amino-α-ketoacids

β-Amino-α-ketoacids are important unnatural amino acids that exhibit unique bioactivity and reactivity derived from the highly electrophilic carbonyl group at the α-position. Despite the broad utility of the motif, reliable synthetic methods for β-amino-α-ketoacids have been limited to the oxidative homologation of α-amino acids based on a chiral-pool approach. In this article, we report an alternative practical method for the asymmetric synthesis of β-amino-α-ketoacid equivalents based on a highly stereoselective organocatalyzed Mannich-type addition using glyoxylate cyanohydrin. The optimal aminothiourea catalyst provides a wide variety of adducts from N-Boc imines in excellent yield and stereoselectivity (up to 100% yield, 99% ee, 94:1 dr), and the reaction can be applied to the direct use of α-amido sulfones as imine precursors, which significantly expands the substrate scope. The experimental structure–activity relationships and computational studies indicated that steric repulsion with the substituent on the amine moiety and the attractive interaction with the bis(trifluoromethyl)phenyl group might contribute to the high diastereoselectivity and that the thiourea scaffold provides a narrower catalytic pocket compared to benzothiadiazine due to the difference in the length of the intramolecular hydrogen bonding, which results in excellent enantioselectivity. The asymmetric adducts can be readily converted into β-amino-α-ketoacids that maintain their optical purity, and these can be used for the decarboxylative formation of amides without purification by column chromatography. Peptide-α-ketoacids were also prepared via intramolecular acyl migration as a key step and applied to decarboxylative peptide coupling with dipeptides that bear various unprotected functional groups and to [2 + 2 + 2] sequential peptide coupling. Furthermore, the efficient synthesis of peptide-α-ketoamides with retention of the stereo-information was achieved by using the cyanohydrin motif at the highly reactive α-carbonyl group, and the synthesis of an α-ketoamide-containing medicine, Telaprevir, was accomplished without any epimerization.

A Review of Ethical and Legal Aspects of Gender-Neutral Human Papillomavirus Vaccination.

While launching a campaign to eliminate cervical cancer, the World Health Organization called to halt human papillomavirus (HPV) gender-neutral vaccination (GNV) because of limited vaccine supply, raising ethical and legal questions about female-only vaccination versus GNV. We identified ethical and legal aspects of HPV GNV by searching MEDLINE for records up to February 19, 2021. We also provided an overview of HPV vaccines, the evolution of HPV vaccine recommendations in North America, and a timeline of male HPV vaccination introduction by searching PubMed, Google, and government websites. Four HPV vaccines are available: Cervarix, Gardasil, Gardasil9, and Cecolin. Vaccine recommendations in North America evolved from female only to eventually include males. Following the FDA's approval of the first HPV vaccine for males (2009), 35 countries began vaccinating males (2011-2020). On the basis of 59 eligible records out of 652, we identified the following constructs: lower male awareness of HPV and vaccination (n = 13), limited economic resources (n = 5), shared social responsibility (n = 18), unprotected groups from female-only HPV vaccination (n = 10), limited screening for HPV-associated noncervical cancers (n = 6), consideration of ethical principles (n = 17), and HPV vaccine mandates (n = 5). Ethical and legal aspects must be considered when recommending vaccination for females only or GNV.

Synthesis of Polyacids by Copolymerization of l-Lactide with MTC-COOH Using Zn[(acac)(L)H2O] Complex as an Initiator.

This work presents the results of research on the preparation of bioresorbable functional polyestercarbonates containing side carboxyl groups. These copolymers were synthesized in two ways: the classic two-step process involving the copolymerization of L-lactide and a cyclic carbonate containing a blocked side carboxylate group in the form of a benzyl ester (MTC-Bz) and its subsequent deprotection, and a new way involving the one-step copolymerization of L-lactide with this same carbonate, but containing an unprotected carboxyl group (MTC-COOH). Both reactions were carried out under identical conditions in the melt, using a specially selected zinc chelate complex, with Zn [(acac)(L)H2O] (where: L-N-(pyridin-4-ylmethylene) phenylalaninate ligand) as an initiator. The differences in the kinetics of both reactions and their courses were pictured. The reactivity of the MTC-COOH monomer without a blocking group in the studied co-polymerization was much higher, even slightly higher than L-lactide, which allowed the practically complete conversion of the comonomers in a much shorter time. The basic final properties of the obtained copolymers and the microstructures of their chains were determined. The single-step synthesis of biodegradable polyacids was much simpler. Contrary to the conventional method, this made it possible to obtain copolymers containing all carbonate units with carboxyl groups, without even traces of the heavy metals used in the deprotection of the carboxyl groups, the presence of which is known to be very difficult to completely remove from the copolymers obtained in the two-step process.

The advent of electrophilic hydroxylamine-derived reagents for the direct preparation of unprotected amines.

Electrophilic aminating reagents have seen a renaissance in recent years as effective nitrogen sources for the synthesis of unprotected amino functionalities. Based on their reactivity, several noble and non-noble transition metal catalysed amination reactions have been developed. These include the aziridination and difunctionalisation of alkenes, the amination of arenes as well as the synthesis of aminated sulfur compounds. In particular, the use of hydroxylamine-derived (N–O) reagents, such as PONT (PivONH3OTf), has enabled the introduction of unprotected amino groups on various different feedstock compounds, such as alkenes, arenes and thiols. This strategy obviates undesired protecting-group manipulations and thus improves step efficiency and atom economy. Overall, this feature article gives a recent update on several reactions that have been unlocked by employing versatile hydroxylamine-derived aminating reagents, which facilitate the generation of unprotected primary, secondary and tertiary amino groups.