The water-base cleavage reaction of 2,2-dialkyl-4-hydroxymethylbenz[f]isoindolinium bromides and chlorides (2b-g) and (4a-g) was investigated. It was established that the above-mentioned salts in water-base cleavage reaction undergo intramolecular recyclization. As a result 1,3-dihydro-4-dialkylaminomethylnaphto[1,2-c]furans (5a-g) are obtained in 62-72% yields. The same products in 65-70% yields may be obtained by step cyclization cleavage reaction of dialkyl-4-hydroxybutyn-2-yl-(3-phenylpropargyl) ammonium salts (1b-g) and (3a-g), as well. The structure of the resulting amines 5a-g are determined and approved by X-ray diffraction, nmr and ir spectroscopic methods.

Keywords: dialkyl(4-hydroxy-2-butynyl)(3-isopropenylpropargyl)ammonium salts, dialkyl(6-methyl-1,3-dihydro-4-isobenzofuranylmethyl)amines, intramolecular cyclization, base catalysis, recyclization.In previous work [1, 2], we showed that dialkyl(4-hydroxy-2-butynyl)(3-phenylpropargyl)ammonium chlorides and bromides or dialkyl(4-hydroxy-2-butynyl)(3-vinylpropargyl)ammonium chlorides and bromides cyclize under base catalysis conditions to give 2,2-dialkyl-4-hydroxymethylbenz[f]isoindolinium or 2,2-dialkyl-4-hydroxymethylisoindolinium salts, respectively. The intramolecular recyclization of these salts was discovered in a study of the stability of these products under aqueous alkaline cleavage conditions using a twofold molar excess of KOH [2, 3]. OH R 2 N O H R 2 N OH R 2 N O R 2 N O OH 1a-e 2a-e 1-3 a R = Pr; b R = C 4 H 9 ; c R+R = (CH 2 ) 4 ; d R+R = (CH 2 ) 5 ; e R+R = (CH 2 ) 2 O(CH 2 ) 2 3a-e 1 3 5 7 --Cl -+ + + Cl -Cl --__________________________________________________________________________________________

A New Intramolecular Recyclization in Water-Base Cleavage Reaction of 2,2-Dialkyl-4-hydroxymethylbenz[f]isoindolinium Bromides and Chlorides. -(CHUKHAJIAN, E. O.; GEVORKYAN, H. R.; CHUKHAJIAN, E. O.; SHAHKHATUNI, K. G.; PANOSYAN, H. A.; TAMAZYAN, R. A.; J. Heterocycl.

In the presence of 0.2 mol of aqueous KOH to 1 mol of the initial salt dialkyl(2-butynyl-4-hydroxy)-(3-R 1 -propargyl)ammonium salts (R 1 = Ph, vinyl, or isopropyl) undergo cyclization, forming 2,2-dialkyl-4-hydroxymethylisoindolinium and 2,2-dialkyl-4-hydroxymethylbenzo[f]isoindolinium salts [1][2][3].While studying the question of the stability of the above-mentioned salts under the conditions of aqueous alkaline cleavage we discovered intramolecular recyclization, which included a stage with cleavage of the isoquinoline ring by the action of the alkoxide ion formed in the alkaline medium and the formation of a dihydrofuran ring [2][3][4][5]. It was established that the recyclization process was facilitated by increase in the number of aromatic rings and by the presence of a methyl substituent in the benzene ring. Thus, heating of the reaction mass for only 40-60 min is required for the recyclization of benzo[5,6;5′,6′-a,c]di[2,2-dialkyl-4-hydroxymethyl]isoquinolinium [5].In order to investigate further the effect of the structure of the initial salts on their cyclization and the subsequent recyclization of the obtained products and also to obtain new potentially active isoindolinium R 2 N Cl O H R 2 N OH R 1 1a-c 2a-c 1a-c R 1 = C 6 H 4 Cl-p, 1, 2 a R = Pr, b R 2 = (CH 2 ) 5 , c R 2 = (CH 2 ) 2 O(CH 2 ) 2 + + 1 1' 3' 1 3 5 8 4 OH -Cl Cl --__________________________________________________________________________________________

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