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Reaction of 2-acyl-6-methylbenzo[b]furan-3-acetic acids and their derivatives such as amides and esters with hydrazine does not give expected 1-alkyl-5H-benzofuro[2,3-e]diazepin-4-ones ones but results in 2-amino-7-methyl-2H-benzo[4,5]furo[2,3-c]pyridin-3-ones or (3-R-6-methylbenzo[b]furan-2-yl)alkyl ketone azines.

Benzo[c]pyrylium salts that contain an acetyl, cyano, or ethoxycarbonyl group in the 4 position of the pyrylium ring were synthesized by the reaction of 3-(3,4-dimethoxyphenyl)pentane-2,4-dione and α-(3,4-dimethoxyphenyl)acetoacetonitrile and ethyl α-(3,4-dimethoxyphenyl)acetoacetate, as well as ethyl α-(3,4-dimethoxyphenyl)benzoylacetate, with acyl perchlorates. It is shown that α-(3,4-dimethoxyphenyl)acetoacetonitrile ethyleneketal is converted to 3-amino-4-acetylbenzo(c)pyrylium salts under these conditions.

The reaction of acyl perchlorates with 1 phenacylskatole affords the previously unknown 1-R-lamethyl-3phenylindolo[2,1-c1-1,4oxazinium salts, which undergo recyclization by the action of ammonia to the corresponding indolo[2,1-alpyrazines. It is found that the salts (R = CHj, CZHS) also form dimers of their anhydro bases. The perchlorate (R = Ph) is converted to indolo[2,141-1, 2, S-triazepine by the action of hydrazine.

A study has been made of thenitrationand bromination of 1-oxo-3,3,6-trimethyl-1,2,3,4-tetrahydrobenzo[bjfuro-, benzo[b]thieno-, and indolo[2,3-c]quinolines. It has been shown that the nitration is directed to the benzene ring (position 10). Bromination by molecular bromine takes place at the 6-CH3 group of the pyridine fragment and yields a mixture of the corresponding nwnobromomethyl and dibromomethyl derivatives, whereas a dimethylacetamide-bromine complex bronzinates the methylene group in position 2, forming the α-bromoketone. The Schmidt reaction of 1-oxo-3,3,6-trimetliyl-1,2,3,4-tetrahydrobenzo[b]furo-, benzol[b]thieno-, and indolo[2,3-c]quinolines have been investigated, as well as conversions of their oximes under conditions of the Beckmann rearrangement.

Treatment of N-phenyl-2-(1-R-indol-3-yl)succinimides with acetyl perchlorate leads to acylation of the benzene ring of the indole substituent.

We have studied the reactions of 3-arylaminobenzofuro-, 3-arylaminobenzothieno-, and 3-arylaminoindolo[2,3-c]pyrylium salts with ammonium acetate, primary amines, and hydrazine hydrate. In an alcoholic medium, primary amines and hydrazine hydrate open up the pyrylium ring to form arylamides of 2-(N-benzylmethylketimine)hetaryl-3-acetic acids or the corresponding hydrazones, where further heterocyclization does not occur. Upon treatment with ammonium acetate in acetic acid, 2-aryl-1-methylhetero[2,3-c]pyridin-3-(2H)-ones are formed along with their 2-unsubstituted analogs.

The recyclization reactions of 4-cyanobenzo[c]pyrylium salts with ammonia, primary amines, and hydrazines have been studied. New derivatives of isoquinoline, benzo-2,3-diazepine, and pyrazolo-[ 5,4-c]isoquinoline have been obtained.

Acid-catalyzed acylation of 3,4-dimethoxyphenylacetone with γ-chlorobutyryl chloride gave 1-(3-chloropropyl)-6,7-dimethoxy-3-methylbenzo[c]pyrylium perchlorate. Recyclization of the product with nitrogen nucleophiles (ammonia, primary amines, hydrazine derivatives, hydroxylamine) led through the corresponding isoquinolinium salts to benzo[f]indolizinium, pyridazino[2,1-b]isoquinolinium, and 1,2-oxazino[2,1-b]isoquinolinium salts.

The examples reported for the recyclization of 3-acylaminobenzo[c]pyrilium salts are limited to their reactions with ammonia [1] and ortho-phenylenediamine [2], although the structure of these compounds would lead us to expect a great variety of transformations. In a study of 3-acylaminobenzo[c]pyrilium salts with nitrogen-containing nucleophiles, we assumed that the formation of 1,3-aminonaphthol derivatives would be possible in their reactions with amines as in the case of 5-alkyl-2-oxobenzo[c]pyrrolo[3,2-e]pyrilium perchlorates [3]. The structure of the products of the reactions of 3-acylamino-1-alkylbenzo[c]pyrilium salts (1) with benzylamine was found to depend on the length of the alkyl substituent at C(1) in the benzo[c]pyrilium cation. Heating 3-acetylamino-6,7-dimethoxy-1-methylbenzo[c]pyrilium perchlorate (1a) with two equivalents of benzylamine gives 3-acetylamino-1-benzylamino-6,7-dimethoxynaphthalene (2), whose structure and composition were indicated by IR and H NMR spectroscopy and elemental analysis. Under the same conditions, salt 1b is converted into the "normal" product, aminonaphthol 3. Recyclization with retention of the acetylamino group was quite unexpected since the reported reactions of 1-acylaminobenzo[c]pyrilium cations feature either loss of the acylamino group [1, 2] or participation of this group in intramolecular recyclization to give 3-hydroxyisoquinoline derivatives [4].

We have found that acylation of N-methallyltoluenesulfonamide (la) with a mixture of acetic anhydride and 70% perchloric acid results in the formation of 2,5-dimethyl-3-tosyl-5acetonyloxazolinium perchlorate (IIa), which undergoes recyclization upon treatment with aqueous ammonia to give 1-tosyl-2,4-dimethylpyrrole (IIIa). Acylation of N-allyltoluenesulfonamide (Ib) gives the oxazollnium salt IIb as a noncrystalline oil, which, upon further workup with aqueous ammonia and subsequent purification by column chromatography yields ltosyl-2-methylpyrrole (IIlb).