Benzotriazoles amide synthesis

A synthesis of 5-(aioylamino)-2-aryloxazoles 39 is outlined in Scheme 9. Heating the glycol 37 (Bt = benzotriazol-l-yl), prepared from glyoxal and benzotriazole, with an amide in the presence of an ion exchange resin yields the acylated diamine 38, which cyclises by the action of sodium hydiide in DMF <95JHC1651>. 

S Kim, A Chang, YK Ko. Benzotriazol-l-yl diethyl phosphate. A new convenient coupling reagent for the synthesis of amides and peptides. Tetrahedron Lett 26, 1341, 1985. 

During the coverage period of this chapter, reviews have appeared on the following topics reactions of electrophiles with polyfluorinated alkenes, the mechanisms of intramolecular hydroacylation and hydrosilylation, Prins reaction (reviewed and redefined), synthesis of esters of /3-amino acids by Michael addition of amines and metal amides to esters of a,/3-unsaturated carboxylic acids," the 1,4-addition of benzotriazole-stabilized carbanions to Michael acceptors, control of asymmetry in Michael additions via the use of nucleophiles bearing chiral centres, a-unsaturated systems with the chirality at the y-position, and the presence of chiral ligands or other chiral mediators, syntheses of carbo- and hetero-cyclic compounds via Michael addition of enolates and activated phenols, respectively, to o ,jS-unsaturated nitriles, and transition metal catalysis of the Michael addition of 1,3-dicarbonyl compounds. ... 

The amidoalkylation of alkenes is a versatile process that is often applied for the synthesis of 5,6-dihydro-4/7-l,3-oxazines <1996CHEC-II(6)301, 1998T1013>. In a recent version of this reaction, T-acyliminium ions were generated from Y-(benzotriazol-l-ylmethyl)amides in the presence of zinc bromide <2001J(P2)530>. 

In the first step amine 11 is coupled with carboxylic acid 15 to form an amide The method employed here for coupling an a-chiral carboxylic acid with an amine was developed in the context of peptide synthesis. Its success is based on DCC-mediated formation (see Chapter 5) of the reactive 1-hydroxy benzotriazole ester 55, which reacts with an amine to give the corresponding amide. In most cases reaction takes place without raccmi/ation, and often in the absence of side reactions that cause other procedures to The alcohol is converted into a silyl ether in the second step. 

The cyclocondensation of 4-alkoxy-l,l,l-trichloro-3-alken-2-ones with hydroxyl-amine using toluene as solvent is more efficient under the action of microwave irradiation than using the classical method (the average time ratio for the two methods is 1 160) [49]. Katritzky et al. have demonstrated the applicability of microwaves to the synthesis of a variety of 2-oxazolines from readily available N-acylbenzotriazoles and 2-amino-2-methyl-l-propanol under mild conditions (80 °C) with short reaction times (12 min). Use of N-acyl benzotriazoles also avoids some complications in microwave reactions, for example dimerization or the exclusive formation of amides from carboxylic acids [50]. 

Phosphoranylideneaminoquinones, e.g. (20), have been prepared in good to excellent yields by the reaction of phosphines with [2,l]benzisoxazole-4,7-quinones, e.g. (19)." A safer alternative to the vinyl azide-based synthesis of (N-vinylimino)phosphoranes (21) has been reported (Scheme 1)." N-(AlkyIthiomethyl)iminophosphoranes (23) have been synthesised from the benzotriazole-substituted iminophosphorane (22) and used without isolation to provide routes to N-alkylthiomethyl-imines, -amides, and -ureas. Tetraazolyl-substituted ylides (25) and (26) are the products of the reaction of vinylphosphonium salts (24) with excess sodium azide." The novel 1,2-1 -azaphosphete (28), which is potentially antiaromatic, has been prepared by the reaction of the azide... 

An easy and convenient one-pot procedure for the synthesis of Weinreb amides <1981TL3815> and hydro-xamates has been reported more recently <2001JOC2534>. The method avoids the use of expensive and toxic coupling reagents such as benzotriazol-l-yl-oxy-tris(dimethylamino)phosphonium hexafluorophosphate (BOP), dicyclohexylcarbodiimide (DCC), and, in addition, the nonfacile removal of their excess from the reaction mixtures (Scheme 60). 

Bt) group in organic synthesis and synthetic methodology. This group also adapted the methodology for a novel preparation of 5-(aroylamino)-2-aryloxazoles 587 (Scheme 1.160). Reaction of l,2-bis(17f-benzotriazol-l-yl)-l,2-ethanediol 583 with two equivalents of an aryl amide affords a l,2-(diaroylamino)-l,2-di(benzo-triazol-l-yl)ethane, 584 in excellent yield. Heating 584 with sodium hydride in... 

Alkynyl(phenyl)iodonium salts have found synthetic application for the preparation of various substituted alkynes by the reaction with appropriate nucleophiles, such as enolate anions [980,981], selenide and telluride anions [982-984], dialkylphosphonate anions [985], benzotriazolate anion [986], imidazolate anion [987], N-functionalized amide anions [988-990] and transition metal complexes [991-993]. Scheme 3.291 shows several representative reactions the preparation of Ai-alkynyl carbamates 733 by alkynylation of carbamates 732 using alkynyliodonium triflates 731 [989], synthesis of ynamides 735 by the alkyny-lation/desilylation of tosylanilides 734 using trimethylsilylethynyl(phenyl)iodonium triflate [990] and the preparation of Ir(III) a-acetylide complex 737 by the alkynylation of Vaska s complex 736 [991]. 

JV-Acylbenzotriazoles (7), generated from carboxylic acids (5) and N(l-methanesulfonyl)benzotriazole (6), react with ammonium hydroxide, primary and secondary amines to form primary (8), secondary (9), and tertiary (10) amides in high yields (Scheme 3) (2000JOC8210). The utility of this simple chemistry is beautifully illustrated by the synthesis of a range of improved mosquito repeUants (2008PNAS7359). 

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