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559The high yield of the lactonization step coupled with the ease of preparation of the ethynesg makes this procedure a potentially useful approach to isocoumarins (1H-benzo-2-pyran-1-ones). The presence of bromine at the 4 position permits ready elaboration to more complex derivatives. Experimental Section 4-Bromo-3-phenyl-lH-benzo-2-pyran-l-one (1).A solution of bromine (0.2 mL) in 10 mL of acetic acid was added dropwise to a mixture of 0.48 g of methyl Z-(Z-phenylethynyl)benzoate? (5a, 2.0 mmol) and 0.25 g of lithium bromide (2.9 mmol) in 10 mL of acetic acid, and the reaction was stirred overnight. The reaction mixture was added to 50 mL of water and the product filtered. The filter cake was washed with water, a sodium thiosulfate solution, and again with water and dried to give 0.47 g of 1: mp (uncorr) 130-131.5 "C (recrystallized from cyclohexane) (lit? 133 "C); mass spectrum, mle (relative intensity) 302 (84), 300

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HYDROGEN BONDIPI'G IN 3-PIPERIDINOLS 1207were vacuum distilled from the residue. The remaining material was dissolved in 3 ml. of benzene and treated with 520 mg. (0.002 mole) of stannic chloride. After 1 hour a t ordinary temperature, the mixture was diluted with ether and extracted successively with 2 N aqueous hydrochloric acid, 2 N aqueous potassium hydroxide and water. The remainder from the dried (MgSOa) ether solution was recrystallized from a mixture of ethanol and water: vield 34 mg. (107'); infrared spectrum: 6.10 p (carbonyl associated with NH); m.p. 250-252°.32 Calcd. for CllHgSO (171.19): C, 77.17; H, 5.30. Found: C, 77.04; H, 5.66.Anal.Diethyl a,a-di-(4-cyanoskatyl)-malonate was isolated from the mother liquors remaining after the crystallization of ethyl a-carboethoxy-~-(4-cyano-3-indole)-propionate1 and was purified by recrystallization from acetone; m.p. 235-237".Anal. Calcd. for CnH24N204 (440.48): C, 69.22; H, 516; N, 11.96. Found: C, 69.10; H, 5.50: N, 11..97.Methyl (4-Carbomethoxy-3-indole)-acetate.-To a solution of 200 mg. (0.001 mole) of 4-cyanogramine and 326 mg. (0.005 mole) of potassium cyanide in 25 ml. of methanol was added, in 4 portions a t 15-minute intervals, 2.0 ml. (0.02 mole) of dimethyl sulfate. After 3 hours a t ordinary tem-(32) Cf. the preparation of this substance by the Fischer procedure from 1,2-cyclopentadione monophenylhydrazone: R . H. F. hlanske, Can.

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