Synthesis Generation Research Articles

ChemInform Abstract: Synthetic Connections to the Aromatic Directed Metalation Reaction. Functionalized Aryl Boronic Acids by ipso Borodesilylation. General Syntheses of Unsymmetrical Biphenyls and m‐Terphenyls.

AbstractThe activated benzenes (I) are boronated by two methods, producing the boronic acids (III).

Synthesis design logic and the SYNGEN (synthesis generation) program

Abstract

Synthetic connections to the aromatic directed metalation reaction. Functionalized aryl boronic acids by ipso borodesilylation. General syntheses of unsymmetrical biphenyls and m-terphenyls

Aryl boronic acids 2a-d and 4a-d obtained by metalation-B(OMe)3 or metalation silylation-ipso borodesilylation sequences, participate in efficient Pd°-catalyzed cross coupling reactions with aryl bromides to give unsymmetrical biphenyls 3a-d and m-terphenyls 5a-d respectively.

ChemInform Abstract: General Syntheses of Natural Products Starting from Symmetrical Compounds (Maleic Anhydride and D‐Mannitol)

Chemischer InformationsdienstVolume 17, Issue 38 Reviews ChemInform Abstract: General Syntheses of Natural Products Starting from Symmetrical Compounds (Maleic Anhydride and D-Mannitol) T. SUZUKI, T. SUZUKISearch for more papers by this author T. SUZUKI, T. SUZUKISearch for more papers by this author First published: September 23, 1986 https://doi.org/10.1002/chin.198638379Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume17, Issue38September 23, 1986 RelatedInformation

A General Synthesis of Diterminal Diamnodideoxyalditols and 1-Amino-1-deoxyalditols Using Trimethylmsilyl Protecting Groups

Abstract General syntheses of diterminal diaminodideoxyalditols and 1-amino-1-deoxyalditols from aldoses are described. Borane-THF reduction of O-trimethylsilylaldaramides, followed by methanolic HC1 workup, leads to diaminodideoxyalditol dihydrochlorides. Similar treatment of O-trimethylsilylaldonamides yields aminoalditol hydrochlorides. The general reaction sequence was used to synthesize six diaminoalditols and five monoaminoalditols. The method is generally applicable to both classes of title aminoalditols and is independent of the chain length and stereochemistry of the starting aldose.

Replacement of the Activated Nitro Group by a Phenylthio Group

Abstract The nitro group, activated by a carbonyl group, alkoxycarbonyl group or a phenyl group, can be replaced by a phenylthio group in the reaction with benzenethiol or its potassium salt. This reaction proceeds in the electron transfer mechanism, and is applicable to the general syntheses of α-phenylthio ketones, α-phenylthio carboxylic esters and α-phenylthio alkylbenzenes from primary nitro compounds.

ChemInform Abstract: Synthesis of Novel Functionalized Hydroxyiminoimines by Direct Nitrosation of β‐Thio‐β‐amino‐α,β‐unsaturated Ketones and Their Further Transformations: New General Syntheses for Imidazole, Quinoxaline and Thiazole Derivatives.

AbstractDurch Umsetzung der ungesättigten Thio‐enamino‐ketone (I) mit Nitrosobenzol erhält man die Imidazole (II); mit Nitrosylchlorid entstehen die Imino‐oxime (III), die zu den Imidazolen (IV) cyclisieren.

Synthesis of novel functionalized hydroxyiminoimines by direct nitrosation of β-thio-β-amino-α,β- unsaturated ketones and their further transformations: new general syntheses for imidazole, quinoxaline, and thiazole derivatives

New general methods for the synthesis of imidazole (3), (10), quinoxaline (6), and thiazole (9) derivatives have been developed from the corresponding novel functionalized 1,2-hydroxyiminoimines (2), (5), and (8) obtained by direct nitrosation of β-thio-β-amino-α,β-unsaturated ketones with nitrosyl chloride.

A convenient synthesis of alkyl- and arylpyrazinyl ketones

Besides alkylpyrazines, pyrazinyl ketones occur as trace constituents in foodstuffs. In addition to other general syntheses of these compounds, a route was explored by which pyrazinecarboxylic esters were reacted with alkyl- and aryl-lithium and magnesium compounds, forming pyrazinyl alkyl and aryl ketones in moderate yields. Although some by-products were formed, the method is direct and convenient. Huang-Minlon reduction of the ketones afforded alkyl and alkaryl-substituted pyrazines.

ON THE EDGE OF THE SIMPSON: Recent additions to understanding of prehistoric artefact distributions in arid Australia

We must move from the traditional model of archaeological knowledge as a GruyA¨re cheese with holes in it to that of a sparse suspension of information particles of varying size, not even randomly distributed in archaeological space and time. The first thing we may deduce from this revision is that many of our taxonomic entity divisions are defined by lines drawn through gaps in the evidence and zones of greatest ignorance ... [Clarke 1973:10]. David Clarke was referring, generally, to the archaeology of regions where the 'cowboy' phase of archaeology is long over, and substantial research and synthesis have already been undertaken. The history of Australian archaeological research suggests that this stage has not yet been reached here, and that many of the general syntheses are premature and serve only to establish our areas of ignorance. Two recent discussions illustrate this. In one case (Hiscock and Hughes 1980) the distribution of backed blades and geometric microliths can be seen to have been defined prematurely, and in the other (Morwood 1979:63-64), Juan knives seem to have been more widely distributed than was previously suspected (see also Horsfall 1982). In this paper I will discuss new finds of geometrics and backed blades and of a Juan knife, and make further comments on distribution studies in Australia.

ChemInform Abstract: Modem Syntheses of Cobalt(III) Complexes. Part 1. Some Modern Methods of General Syntheses (94 Literaturzitate).

Chemischer InformationsdienstVolume 14, Issue 47 Reviews ChemInform Abstract: Modem Syntheses of Cobalt(III) Complexes. Part 1. Some Modern Methods of General Syntheses (94 Literaturzitate). M. SHIBATA, M. SHIBATASearch for more papers by this author M. SHIBATA, M. SHIBATASearch for more papers by this author First published: November 22, 1983 https://doi.org/10.1002/chin.198347353AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume14, Issue47November 22, 1983 RelatedInformation

Cesium fluoride promoted formation of n-chloro and n-bromo amines and imines

Cesium fluoride is a very effective reagent for the fluoride promoted oxidation of nitriles and imines by Cl 2, Br 2 and BrCl. Previous work by us had demonstrated that CsF fluoride was effective in promoting the oxidation of R fCFNF by Cl 2 and Br 2 to R fCF 2NFCl and R fCF 2NFBr, the oxidation of R fCN to R fCF 2NCl 2 by Cl 2 and the apparent oxidation of R fCN to R fCF = NBr by Br 2 (S.C. Chang and D.D. DesMarteau, Inorg. Chem. 1983, 48 , 771). We have now made a detailed investigation of the CsF promoted oxidation of R fCN, NCCFNF, CF 2NCl, (CN) 2 and CF 3NCFR x by Cl 2, Br 2 and BrCl. Significant results to be discussed will include the general high yield syntheses of R xCFNBr, CF 3N(Cl)CF 2R x, a comparison of the reactivity of −CN -vs- −CFNF in NCCFNF, the stepwise halogenation of (CN) 2 by Cl 2 and Br 2, the novel compounds CF 3NBrCl and CF 3NBr 2 from CF 2NCl and the unique CsF promoted conversion of R fNCl 2 by Br 2 to R fNBrCl and R fNBr 2. Furthermore, the utility of BrCl-vs-Cl 2 in the formation of certain N-chloro compounds will be shown.

“Umpulong” of reactivity at the C-6 position of uridine: a simple and general method for 6-substituted uridines

Lithiated 2′,3′-O-isopropylidine-5′- O -methoxymethyl-uridine was found to react with a variety of electrophilic reagents regiospecifically at the C-6 position. The protecting groups of the ribose moiety in the 6-functionalized products were concurrently removed under mild conditions with aqueous trifluoroacetic acid. Consequently, the present method permits simple and general syntheses of 6-substituted uridines.

Synthesis of esters of saturated and unsaturated sixteen-carbon acids deuterated at the terminal or penultimate carbons

General syntheses of saturated and unsaturated fatty acids, specifically trideuterated at the terminal carbon or dideuterated at the penultimate carbon, from ω-hydroxy esters, have been developed. Methyl [16- 2H 3]hexadecanoate was synthesized from methyl 16-hydroxyhexadecanoate. The hydroxyl group was protected as the tetrahydropyranyl ether and the ester group reduced with lithium aluminum deuteride, first to an alcohol and then, by way of the derived mesylate, to a trideuteromethyl group. The new ester group was formed by oxidation of the hydroxyl group. Methyl 16-hydroxy[2- 2H 2]hexadecanoate was prepared, from 16-hydroxy-hexadecanoate, by exchange of the α protons and, by the reductive route above, with lithium aluminum hydride, gave methyl [15- 2H 2]hexadecanoate. Methyl 16-hydroxy-7-hexadecynoate was synthesized from 6-chlorohexanol and was converted, by means of the above reactions, to methyl [16- 2H 3]- and [15- 2H 2]-9-hexadecynoates. Lindlar reduction gave methyl [16- 2H 3]- and [15- 2H 2] cis-9-hexadecenoates. Overall yields ranged from 30% to 38%.

9-Oxobenzomorphans. I. General syntheses of dihydrobenz[e]indolines as key intermediates

Various 5,9b-dihydrobenz[e]indolines were synthesized by three general methods: (a) by alkylation with the appropriate alkyl halide of 1,2,4,5-tetrahydro-1H-benz[e]indoles, themselves obtained by alkylation with bromochloroethane of enamines derived from 7-alkoxy-2- tetralones; (b) from 1-alkylaminoethyl-2,2-ethylenedioxy-1,2,3,4-tetrahydronaphthalenes by acid hydrolysis, and (c) by reduction of 2-oxo-2,3,5,9b-tetrahydro-1 H-benz[e]indoles which in turn were obtained from ethyl 2-oxo-1,2,3,4-tetrahydro-1-naphthalene acetates by reaction with methylamine followed by dehydration. These substances are key intermediates in the synthesis of 9-oxobenzomorphans.

Allgemeine Synthesen und rationelle Strukturparameter isomerer Derivate von [3,4]‐kondensierten Pyrazolen

General Syntheses and Rational Parameters for Structural Assignment of Isomeric Derivatives of [3,4]‐fused Pyrazoles4 isomeric 1‐ or 2‐methyl‐, and 1‐ or 2‐benzyl‐pyrazolo[3,4‐b]pyridones, i.e. the 4‐oxo‐types17a, bor11a, band the 6‐oxo‐types16a, bor10a, b, are synthesized unambiguously. Cyclisation of 1‐substituted 3‐ or 5‐(1‐methyl‐2‐ethoxycarbonyl‐vinylamino)‐pyrazoles9a, bor.15a, b, which were synthesized from 1‐substituted 3‐ or 5‐amino‐pyrazoles and ethyl acetoacetate yields11a, bor17a, bin downtherm, but10a, bor16a, bin presence of acidic catalysts. The acidic cyclisation is preceded by a new rearrangement of9or15into 1‐ substituted 3‐27or 5‐amino‐4‐(1‐methyl‐2‐ethoxycarbonyl‐vinyl)‐pyrazoles30; mechanism and concurring reactions are explained. Because of their higher electron densities at C‐4 it is easier to cyclise derivatives of 5‐amino‐pyrazoles compared to 3‐amino‐pyrazoles. All isomeric 1‐ or 2‐substituted 4(6)‐chloro‐6(4)‐methyl‐pyrazolo‐[3,4‐b]pyridines are formed with POCl3from the corresponding oxo‐compounds.The position of a substituent at N‐1 or N‐2 of [3,4]‐fused pyrazoles can be assigned using the significant1H‐n.m.r.‐parameter Δ= δ— − δHMPT(conc. HC—3). If solvent influences are considered, δ(C  O) is a useful13C‐n.m.r.‐parameter to distinguish the 4‐oxo‐types (11a, b; 17a, b) from the 6‐oxo‐types (10a, b; 16a, b) of pyrazolo[3,4‐b]pyridones. Further own and lit. dates conc. structural assignment (n.m.r., i.r., u.v.) are discussed critically.

Die Reaktion von α,β‐Dihalogen‐propionitrilen mit monosubstituierten Hydrazinen ‐ einfache Synthese 1‐substituierter 3‐ bzw. 5‐Amino‐pyrazole

The Reaction of α,β‐Dihalogeno‐propionitriles with Monosubstituted Hydrazines — A Simple Synthesis of 1‐Substituted 3‐ or 5‐Amino‐pyrazolesIn methanol hydrazines 3, and α,β‐dihalogeno‐propionitriles 1, 2 even at 0°C irreversibly yield 3 · HX, and α‐halogenoacrylonitriles 4, 5 (A1). Fast addition of alkyl‐ and aralkyl‐ hydrazines 3 to 4, 5 (C) gives 1‐substituted 1‐(2′‐halogeno‐2′‐cyan‐ethyl)‐hydrazines 6, the addition of arylhydrazines 3 to 4, 5 (D) 1‐aryl‐2‐(2′‐halogeno‐2′‐cyan‐ethyl)‐hydrazines 8. In methanol 6 spontaneously cyclise (E) to hydrogen halides 7 · HX of 1‐alkyl‐ and 1‐aralkyl‐3‐amino‐pyrazoles, 8 with 2 moles of acids (F) to salts 10 · 2HY of 1‐aryl‐4‐halogeno‐5‐imino‐pyrazolidines, and the free 10 spontaneously (G) to hydrogen halides 9 · HX of 1‐aryl‐5‐amino‐pyrazoles. Mechanisms (A1), (C), (D), (E), (F), and (G) are proved by t.l.c., 1H‐n.m.r., and isolation of intermediates, the structures of 7 resp. 9, using the significant 1H‐n.m.r.‐parameter Δ. Simple general syntheses are described for 3‐amino‐pyrazoles 7 (R = H, alkyl, aralkyl) or 5‐amino‐pyrazoles 9 (R = aryl) starting with α,β‐dihalogeno‐propionitriles 1, 2, and for α‐bromo‐acrylonitrile 5.

ChemInform Abstract: ASYMMETRIC CATALYSIS BY CHIRAL RHODIUM COMPLEXES IN HYDROGENATION AND HYDROSILYLATION REACTIONS

AbstractZur Darstellung von asymmetrischen Verbindungen ist eine asymmetrisch katalysierte Reaktion einer stöchiometrischen asymmetrischen Synthese vorzuziehen.

Untersuchungen über Protein- und RNA-Synthese in dormanten und nachgereiften Samen von Melandrium noctiflorum

Summary In Melandrium noctiflorum seeds germination and the capacity for general protein and RNA syntheses are not directly correlated. Dormant and afterripened seeds of the harvest 1974 do not show any differences in 14 C-alanine and 3 H-uracil incorporation after soaking 12 and more hours under different conditions which can induce (paper factor, red and white light) or inhibit (far-red light, 30°C) germination. However, there are differences in the start of protein and RNA syntheses in dependence of the physiological state of the seeds. RNA, and especially protein syntheses in dormant seeds start earlier than in afterripened ones. When afterripened seeds were brought to a second dormancy by long-time irradiation with far-red, a high level of 14 C-alanine incorporation occurs. Therefore we conclude that bulk protein and RNA syntheses do not control germination of these seeds. Ethylene is partially able to break dormancy of Melandrium noctiflorum seeds, especially in combination with white light, but there is no enhanced incorporation of 14 C-alanine and 3 H-uracil into ethylene treated seeds, too. Nevertheless, there is a rapid inhibition of germination by reducing protein and RNA syntheses after application of the specific inhibitors, cycloheximide and 2-thiouracil. According to these results dormancy of Melandrium noctiflorum seeds seems not to be caused by a general but by a specific metabolic block.

Ｒｅｔｒｏ Ｍａｓｓ Ｓｐｅｃｔｒａｌ Ｓｙｎｔｈｅｓｉｓ による天然物の全合成

Retro Mass Spectral Synthesis, which was named by the authors for the retro-process of mass spectral fragmentation and provides an effective method for designing synthetic approach to the total synthesis of several natural products, is explained. Some examples of new general syntheses for ring systems of natural products through “Retro Mass Spectral Synthesis” were reviewed.