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This paper deals with the preparation of ethyl benzofuro[3,2-b]pyrrole-2-carboxylate, its hydrolysis, N-alkylation, and reduction. Also the synthesis of new heterocyclic systems, benzofuro[3,2-b]pyrrole and 2H-dihydrobenzofuro[2',3':4,5]pyrrolo[1,2-d]-1,2,4-triazin-1-one, is described. The structure of 14 new substances was corroborated by IR, UV, 1H NMR, 13C NMR and electron impact mass spectra.

This paper describes the preparation of furo[2',3' :4,5]pyrollo[1,2-d]-1,2,4-triazolo[3,4-f]-1,2,4-triazines (V) from 4H-furo[3,2-b]pyrolle-5-carboxhydrazide (I, and benzo[b]furo[2',3' :4,5]-pyrrolo[1,2-d]-1,2,4-triazolo[3,4-f]-1,2,4-triazines (VIII) from 1H-benzo[b]furo[3,2-b]pyrrole-2-carboxhydrazide. Compound I reacts with triethyl orthoformate or orthoacetate to give 1,2-dihydro[2',3'-4,5]pyrrolo[1,2-d]-1,2,4-triazin-1-one or its methyl analogue II. Compounds of general formula II afford with phosphorus pentasulfide thiones III; III yields IV with hydrazine. Cyclization of IVwith triethyl orthoformate or orthoacetate furnished compounds V. Similarly, VIgives with hydrazine VII, which, upon reaction with triethyl orthoformate or orthoacetate affords VIII.

A series of 5-aryl-2-furancarbaldehyde 2,6-dialkylphenylhydrazones (Ia - Iv) and dimethylhydrazones (IIa - IIf) as well as related compound benzo[b]furan-2-carbaldehyde dimethylhydrazone (III) were prepared. Compounds Ia - Iv were synthesized by condensing 5-aryl-2-furancarbaldehydes with 2,6-dialkylphenylhydrazines, compounds IIa - IIf were obtained from the same starting compounds and N,N-dimethylhydrazine. The intermediate 5-aryl-2-furancarbaldehydes were prepared by reaction of aryldiazonium chlorides with 2-furancarbaldehyde. The structure of the compounds were proven by 1H, 13C and 15N NMR spectra.

Substituted 1-(6-methoxy-2-benzothiazolyl)-2-pyridones 5a-5f have been prepared from N-(6-methoxy-2-benzothiazolyl)cyanoacetamide (2) which on reactions with 4-substituted benzaldehydes gives 3-aryl-2-cyano-N-(6-methoxy-2-benzothiazolyl)-2-propenamides 4a-4g. Derivatives 4a-4f were cyclized with malonodinitrile in the presence of piperidine to give the corresponding 2-pyridones 5a-5f. The IR, UV, 1H NMR and mass spectra of the substances synthesized are discussed.

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