Acylamides, synthesis

Thiation is used predominantly for the synthesis of annelated thiazoles (e.g., (109)—(111)) from heterocyclic acylamides bearing either adjacent phenol or halogen substituents (Equations (33)— (35)) (70KGS1624, 77KGS1495, 87KGS410). The thieno[3,2-c]isothiazolium perchlorate (113) was obtained from the 2-benzoyl-3-(phenylamino)thiophene (112) by sequential reaction with phosphorus pentasulfide and perchloric acid (Equation (36)) <77CJC1123>. 

Quinazolin-4(3//)-one and derivatives 17 with substituents at the benzene ring and/or the 2-position are conveniently prepared in high yield by fusing anthranilic acid derivatives 16 with amides or thioamides. The synthesis was first reported by von Niementowski in 1895 and is best suited for the preparation of 2-unsubstituted quinazolin-4(3i/)-ones by the fusion of anthranilic acid derivatives with formamide. Homologous acylamides require higher tempera-... 

The cyclization of acylamides with amines or ammonia has been useful on occasion, for example, in the synthesis of 1-arylimidazolinones (212) from benzoxazolones (Scheme 145) <80CL659, 86CPB3U1,88CHE1129>. 

A mechanistic rationale that explains the formation of acyl isocyanates, mixed anhydrides, and A-acylamides from ozonolysis of substituted oxazoles was pre-sented by Kashima s group. In addition, Kashima and co-workers adapted their methodology for peptide synthesis (Scheme 1.204). Here, the starting amino acid was readily converted to a 5-phenyloxazole analogue 740 in several straightforward steps. Ozonolysis of 740 followed by reaction with glycine methyl ester... 

Scheme 6.30 AFC alkylation of pyrroles with p-trifluoromethylated acylamide 84 and synthesis of trifluorinated heliotridane 87 reported hy Shibata.

The treatment of alkyl borates, phenylboronic acid, and boric acid with amidoximes has resulted in the synthesis and characterization of twenty-seven 1,3,5,2-oxadiazaboroles. Dimeric amidoboranes which result in boron-nitrogen-oxygen heterocyclic systems as well as monomeric iminoboranes in equilibrium with monomeric amidoboranes are produced from the reaction of iVD-bis(trimethylsilyl)acylamides with halogenodiorganylboran. ... 

Noltes (96) recently reported the synthesis of a number of iV-trialkyltin-substituted acylamides and carbamates by the reaction of trialkyltin alkoxides with the corresponding NH deriAratives. At elevated temperatures (150°-160°C) such reactions proceed in excellent yields (67-90%). The formation of iV-triethylstannylacetanilide is given as an example. 

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