Abstract
Benzotriazole is a very useful synthetic auxiliary with versatile applications in organic chemis¬try. We have used benzotriazole in the synthesis of various heterocyclic compounds (benzoxazine, quinazoline, triazinetrione, hydantoin, oxadiazine and diazepane derivatives), amino acid derivatives, car¬bamates, ureas, semicarbazides, carbazides, sulfonylureas, sulfonylcarbazides, hydantoic acids, non-steroidal antiinflammatory drug (NSAID) and primaquine derivatives, polymer-drug and thiomer-drug conjugates. The results have been published in more than 30 papers and here we give an overview of all syntheses.
Highlights
Benzotriazole is an aromatic five-membered heterocyclic compound condensed with benzene
The reactions proceeded through N-carboxy amino acids (NCA) intermediates 39.34
Were obtained, which after catalytic hydrogenation gave 1-acyl-4-hydroxysemicarbazides 54.44 1-Acyl-5-substituted carbazides 55 were the products of the reaction of nonsteroidal antiinflammatory drug (NSAID) hydrazides 48 and 1-(1-benzotriazolecarbonyl)4-benzyloxysemicarbazide 7a
Summary
Benzotriazole is an aromatic five-membered heterocyclic compound condensed with benzene. Double role of Btc group as N-protecting /C-activating was observed in direct preparation of amino acid esters 42, amides 32, hydroxamic acids 43 and di- and tripeptides 40 from starting compounds 24 and corresponding alcohols, amines, hydroxylamines and amino acids or dipeptides (Scheme 5).[23,25,29,33] The reactions proceeded through N-carboxy amino acids (NCA) intermediates 39.34. The reactions of NSAIDs with chloride 1 gave intermediate mixed anhydrides, which decarboxylated to NSAID benzotriazolides 44, stabile solids with activated carboxylic moiety.[35] Compounds 44 readily reacted with a number of nucleophiles (alcohols, amines, hydroxylamines, hydrazine and polymers) under mild conditions yielding esters,[35,36,37] amides 46,36,38–41 hydroxamic acid 47,42,43 hydrazides 48,44 hydroxyamides 49,45 and polymer-NSAID and thiomer-NSAID conjugates 5035,37,46–48 (for more information see the last paragraph). They reacted with 1-(N-alkyl/arylcarbamoyl)benzotriazoles 2, yielding 1-acyl-4-substituted semicarbazides 52.44 If the reaction was performed with 1-(N-benzyloxycarbamoyl)benzotriazole 2a, benzyloxysemicarbazides 53
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