Tosyl Isocyanate Research Articles

ChemInform Abstract: A Facile Highly Regio‐ and Stereoselective Preparation of N‐Tosyl Allylic Amines from Allylic Alcohols and Tosyl Isocyanate via Palladium(II)‐Catalyzed Aminopalladation—β‐Heteroatom Elimination.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A facile highly regio- and stereoselective preparation of N-tosyl allylic amines from allylic alcohols and tosyl isocyanate via Palladium(II)-catalyzed aminopalladation-beta-heteroatom elimination

The high regio- and stereoselectivity have been obtained from the allylic substitution reaction catalyzed by palladium(II) species. From allylic alcohols, one-pot reaction with tosyl isocyanate followed by palladium(II)-catalyzed allylic substitution gives N-tosyl (E)-allylic amines in high yield. The substitution occurs only at the gamma-position of the 1- or 3-substituted allylic alcohols.

Carbonic Anhydrase Inhibitors. Arylsulfonylureido-and Arylureido-Substituted Aromatic and Heterocyclic Sulfonamides: Towards Selective Inhibitors of Carbonic Anhydrase Isozyme I

Reaction of twenty aromatic/heterocyclic sulfonamides containing a free amino, imino, hydrazino or hydroxyl group, with tosyl isocyanate or 3,4-dichlorophenyl isocyanate afforded two series of derivatives containing arylsulfonylureido or diarylureido moieties in their molecule respectively. The new derivatives were assayed as inhibitors of three carbonic anhydrase (CA) isozymes, CA I, II (cytosolic forms) and IV (membrane-bound form). Potent inhibition was observed against all three isozymes but especially against CA I, which is generally 10-75 times less susceptible to inhibition by the classical sulfonamides in clinical use as compared to the other major red cell isozyme, CA II, or the membrane-bound one, CA IV. The derivatives obtained from tosyl isocyanate were generally more potent than the corresponding ones obtained from 3,4-dichlorophenyl isocyanate. This is the first reported example of selective inhibition of CA I and might lead to more selective drugs/diagnostic agents from this class of pharmacologically relevant compounds.

The antifungal activity of sulfonylamido derivatives of 2-aminophenoxathiin and related compounds

Aryl/alkyl-sulfonylamido, arylsulfenylamido, arylcarboxamido and ureido/thioureido derivatives of 2-aminophenoxathiin were prepared by reaction of the title compound with sulfonyl/sulfenyl halides, sulfonic acid anhydrides, acyl chlorides, tosyl isocyanate, aryl/allyl isocyanates or isothiocyanates. Some of these derivatives, containing free amino groups, have been further derivatized by reaction with 2,4,6-trisubstituted-pyrylium salts, aryl/allyl isocyanate/isothiocyanates or tosyl isocyanate. Several of the newly synthesized compounds act as effective antifungal agents against Aspergillus and Candida spp., some of them showing activities comparable to ketoconazole or itraconazole (against the aspergilli) but being much less effective against Candida. The mechanism of action of these compounds involves inhibition of ergosterol biosynthesis, and probably interaction with lanosterol-14-α-demethylase (CYP51A1), since reduced amounts of ergosterol were evidenced by means of HPLC in cultures of the sensitive strain A. niger treated with some of these inhibitors. Thus, the two classes of antifungal compounds, i.e. the azoles and the new derivatives reported here, might possess a similar mechanism of action at molecular level.

Synthesis and Properties of 9-(Tropylidenehydrazono)fluorene and Related Compounds

Abstract 9-(Tropylidenehydrazono)fluorene (1) was obtained by a reaction between 9-fluorenone hydrazone and tropylium tetrafluoroborate, accompanied by 9-fluorenone azine, 9-(benzylidenehydrazono)fluorene, and 9,9-ditropylfluorene. The amination of 1 occurred at the 2-position of the tropylidene moiety. The addition of tosyl isocyanate to 1 gave the [8 + 2] cycloadduct at the 2,4,6-cycloheptatrien-1-imine structure.

Sulfonylamido derivatives of 2-aminophenoxathiin-10,10-dioxide and related compounds possess antifungal action due to the possible inhibition of lanosterol-14-alpha-demethylase.

Aryl/alkyl-sulfonylamido-, arylsulfenylamido-, arylcarboxamido-, and ureido/thioureido derivatives of 2-aminophenoxathiin-10,10-dioxide were prepared by reaction with sulfonyl/sulfenyl halides, sulfonic acid anhydrides, acyl chlorides, tosyl isocyanate, aryl/allyl isocyanates or isothiocyanates. Some of these derivatives, containing free amino groups, were further derivatized by reaction with 2,4,6-trisubstituted-pyrylium salts, aryl/allyl isocyanate/isothiocyanates or tosyl isocyanate. Several of the newly synthesized compounds act as effective antifungal agents against Aspergillus and Candida spp., some of them showing activities comparable to ketoconazole, with minimum inhibitory concentrations in the range of 0.3-0.5 microgram/mL. Their mechanism of antifungal action is hypothesized to be due to inhibition of lanosterol-14-alpha-demethylase.

Thermal or Lewis acid-promoted electrocyclisation and hetero Diels–Alder cycloaddition of α,β-unsaturated (conjugated) carbodiimides: a facile synthesis of nitrogen-containing heterocycles

α,β-Diarylvinyl- and α-styryl-carbodiimides, prepared by the aza-Wittig reaction of iminophosphoranes with isocyanates, underwent either 6π-electrocyclisation upon heating or a Diels–Alder reaction under thermal or Lewis acid-promoted conditions with appropriate dienophiles such as tetracyanoethylene, dimethyl acetylenedicarboxylate, maleimide, ethyl propiolate and tosyl isocyanate, to give isoquinolines, pyridines, oxazines, pyrimidines and pyrrolopyridines. In contrast, β-styrylcarbodiimide was entirely unreactive toward either the electrocyclisation or the Diels–Alder reaction even under severe reaction conditions. 4-Coumarylcarbodiimide underwent an inverse electron-demand Diels–Alder reaction with an enamine either thermally or in the presence of a Lewis acid catalyst to afford chromenopyridines. Thus experimentally observed reactivity differences of the substituted vinylcarbodiimides toward the pericyclic reactions were rationalised by considering not only the heats of formation but also the probability of the existence of reactive conformers that were estimated by semi-empirical (AM1) and molecular mechanics calculations.

Carbonic anhydrase inhibitors: inhibition of isozymes I, II and IV with N-hydroxysulfonamides--a novel class of intraocular pressure lowering agents.

A series of N-hydroxy sulfonamides has been prepared by reaction of alkyl-, arylalkyl- and arylsulfonyl halides or sulfonic acid anhydrides with hydroxylamine. Structurally related inhibitors were also obtained from acyl chlorides and hydroxylamine, as well as by reaction of tosyl isocyanate with hydroxylamine, sulfamic acid and sulfamide. Inhibition of three carbonic anhydrase (CA) isozymes, hCA I, hCA II and bCA IV (h = human; b = bovine) with the prepared compounds has been investigated. Good inhibitors, as well as compounds with moderate activity against these isozymes were detected, depending on the R group to which the SO2NHOH or CONHOH moieties were attached. Susceptibility to inhibition was generally: hCA II > bCA IV >> hCA I. Some of the new inhibitors showed very good antiglaucoma action when administered directly into the eye in experimental animals, acting as more efficient intraocular pressure lowering agents as compared to the clinical drug dorzolamide. This constitutes an encouraging result for obtaining novel antiglaucoma drugs from this class of CA inhibitors.

Enantiospecific and diastereoselective synthesis of syn- β-amino-α-hydroxy acids

The reaction of chiral α-hydroxy β,γ-unsaturated esters with tosyl isocyanate followed by cyclization of the resulting allylic carbamates with iodine in the presence of sodium carbonate provided trans-4,5-disubstituted 2-oxazolidinone derivatives in a highly diastereoselective manner. The subsequent removal of the iodo group and the protective functionality afforded the syn- β-amino-α-hydroxy acids. Using the reaction sequence, (2 R,3 S)- and (2 S,3 R)-3-amino-2-hydroxy acids were synthesized with high enantioselectivity.

Sulfonylamido derivatives of aminoglutethimide and their copper(II) complexes: a novel class of antifungal compounds

Summary Reaction of aminoglutethimide (3-( 4 -aminophenyl)-3-ethyl-2,6-piperidinedione) with sulfonyl halides or sulfonic acid anhydrides affords a series of 3-[ 4 -(alkyl/arylsulfonylamido)phenyl]-3-ethyl-2,6-piperidinediones. Some of these derivatives, containing free amino groups, have been further derivatized by reaction with 2,4,6-trimethylpyrylium perchlorate, 3,4-dichlorophenyl isocyanate or tosyl isocyanate. Cu(II) complexes containing as ligands the conjugate bases of some of these compounds have also been obtained. The new derivatives generally act as moderate antifungal agents against Aspergillus and Candida spp , but one of them shows activities comparable to ketoconazole.

ChemInform Abstract: A Highly Efficient Synthesis of (‐)‐PI‐091 Construction of the 4‐ Alkoxy‐2‐butene‐4‐lactam Skeleton from Fischer‐Type Carbene Complexes, Alkynyllithiums, and Tosyl Isocyanate.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A Highly Efficient Synthesis of (-)-PI-091 Construction of the 4-Alkoxy-2-butene-4-lactam Skeleton from Fischer-Type Carbene Complexes, Alkynyllithiums, and Tosyl Isocyanate.

A Highly Efficient Synthesis of (-)-PI-091 Construction of the 4-Alkoxy-2-butene-4-lactam Skeleton from Fischer-Type Carbene Complexes, Alkynyllithiums, and Tosyl Isocyanate.

ZWITTERIONIC SPECIES FROM TRIISOPROPYLPHOSPHINE AND 2-CYANOACRYLATES: SYNTHESIS, STRUCTURE AND PROPERTIES

Abstract Triisopropylphosphine reacts with 2-cyanoacrylates with formation of the P-zwitterionic species 2a and 2b. The reaction of 2b with trimethylsilyltriflate, in the presence of traces of water, leads to the phosphonium triflate 3. 2b is alkylated at the carbon atom with methyl iodide with formation of the phosphonium iodide 4. The initially formed adducts of the zwitterionic species 2a and 2b with tosyl azide and with tosyl isocyanate are thermodynamically unstable. In the first case, the final products of the reaction are tosyl iminotriisopropylphosphine imide 6 and 2-cyanoacrylate polymers. In the second case, the reaction leads to the zwitterionic product 8, and, in the presence of traces of water, to the molecular complexes 9a and 9b. The reaction of the zwitterionic species 2a and 2b with methylisocyanate proceeds in an unusual way, resulting in the formation of the zwitterionic species 12a and 12b, as a result of the insertion of methylisocyanate into the C[sbnd]C bond of the starting zwitteri...

Synthesis of new imidazo[4,5‐d][1,3]diazepine derivatives from 5‐amino‐4‐(cyanoformimidoyl)imidazoles

AbstractN1‐[(Z)‐2‐Amino‐1,2‐dicyanovinyl]formamidines 1a‐d react readily with tosyl isocyanate to form novel 8‐amino‐3‐substituted‐5‐oxo‐7‐tosylaminoimidazo[4,5‐d][1,3]diazepines 6a‐d rather than the 6‐cyano‐2‐oxopurine derivatives 5a‐d expected. Compound 5a has been synthesized from 1a by reaction with ethyl chloroformate and base‐catalyzed cyclization of the resultant 5‐ethoxycarbonylamino‐4‐(cyanoformimidoyl)imidazole. Treatment of the 5‐amino‐4‐cyanoimidazoles 7a and b with tosyl isocyanate under similar conditions gives the 4‐cyano‐5‐(3′‐tosylureido)imidazoles 8a and b, which on treatment with ethanolic ammonia cyclizes to the corresponding isoguanines 10a and b.

Tin for organic synthesis. 10. Unconventional regiospecific syntheses of aromatic carbonamides and thiocarbonamides by means of tin-mediated Friedel-Crafts reactions

Friedel-Crafts reactions of stannylarenes 1 with tosyl isocyanate (TsNCO, 2) give N-tosylcarbonamides 3 via ipso substitution of the stannyl group. Thus, unconventionally substituted aromatic carbonamides can be obtained. The combination of the reaction of 1 and 2 with that of 1 and chlorosulfonyl isocyanate (14) allows one-pot syntheses of N-(arylsulfonyl)-substituted aromatic carbonamides with optional substitution patterns on both aromatic rings. The known ipso-specific substitutions of stannylarenes with 14 are extended to bi- and tricyclic arenes as well as to thiophenes 6 and 22. One stannyl group can serve as a leaving group for two aromatic systems, as shown with diaryldialkyltins 29. Also, stannylalkanes such as 27 react with 14 to afford alkylsulfonyl isocyanates and products of further reactions, such as 28. From the reactions of 1 with ethoxycarbonyl isothiocyanate (32), ortho- and meta-substituted aromatic thiocarbonamides 33 which are potential precursors for further syntheses, are accessible. The scope, limitations, and mechanism of these electrophilic substitutions are outlined

Reversibility of the [2 + 2] Cycloaddition of Isocyanates to Glycals

Abstract[2 + 2] Cycloadducts obtained by the addition of tosyl isocyanate to glycals (10 – 13) undergo retro‐addition upon heating or even at room temperature. The rate of retro‐addition increases with rising temperature and polarity of the solvent.

Some Properties of Cyclopropenone Oximes under Beckmann Reaction Conditions

Abstract The reaction of diphenylcyclopropenone oxime (1a) with acetyl or tosyl isocyanate, carboxylic anhydrides, or nitrohalobenzenes yielded the cyclopropenone O-substituted oxime derivatives. Treating with thionyl bromide and chloride 1a gave 3-haloacrylonitriles. Whereas 1a as well as other cyclopropenone oximes, were stable under acidic conditions, heating in methanolic sodium hydroxide gave the ring-opened α,α-dimethoxyketones oximes.

ChemInform Abstract: Synthesis of β‐Lactams from Sugar Vinyl Ethers and Isocyanates.

AbstractCycloaddition reaction of sugar vinyl ethers such as (I) with tosyl isocyanate (II) produces N‐tosyl β‐lactams such as (III) which are N‐deprotected upon treatment with sodium in liquid ammonia.

Synthesis of (R)-N-Tosylemeriamine via ChiralN-Tosylimidazolidin-2-ones

The total syntheses of 3,4-diaminobutanoic acid (1) and (R)-N-tosylemeriamine (2e; 4-trimethylammonio-3-tosylamino-butanoate) are described, starting from methyl 4-[(S)-(1-phenylethyl)amino]-2-butenoate (3) and tosyl isocyanate through an intramolecular Michael addition. The intermediate 5R and 5S 5-(methoxycarbonylmethyl)-3-[(S)-1-phenylethyl]-1-tosylimidazolidin-2-ones (4) and (5) are easily separated and their absolute configuration at C-5 is assigned by means of 1H NMR spectroscopy.

Synthesis of β-lactams from sugar vinyl ethers and isocyanates

[2+2] Cycloaddition of tosyl isocyanate to sugar vinyl ethers followed by N-deprotection affords β-lactams with fairly good asymmetric induction.