Scientia Sinica

No. 1 CHANG: STUDIES ON FUSED RING SYSTEMS Il 59

‘ts volume and left standing in the ice box, colourless crystals separated out. This was filtered and amounted to 2.6 g; m.p. 72-85° (second fraction). The filtrate from the second fraction is the third fraction. At present, no further work has been done on the separation of the diastereoisomers from these two fractions as yet, and this work will be continued in the future.

Methyl /-1-Hydroxy-2-methyl-2-carbomethoxy-7-methoxy-1,2,3,4,9,10,11,12octahydrophenanthrene-l-acetate (XVI). —Reformatsky reaction between 0.4 g of the -keto ester (m.p. 114-116°) and methyl bromoacetate was carried out according to the procedure described for the preparation of the d-enantiomorph (XII). The yellow oily product (0.4 g), after repeated recrystallizations from methyl alcohol, formed colourless needles; m.p. 86-S8° (began to soften at

52°).

Rotation. A solution of 0.018 g of the hydroxy ester in 10 ml of absolute ethyl alcohol gave 2—0.203, [@]p—113°. .

Analysis. Calcd. for Cy;HsgO5: C, 67.00; Ein Je50% Found ; C, 67.20; H, 7.65.

SUMMARY

1. By use of acetic acid purified over chromium trioxide as solvent, 5% Pd-C as catalyst, y-(6-methoxy-2-carboxy-3,4-dihydro-I-naphthyl) -butyric acid was smoothly reduced to y-(6-methoxy-2-carboxy-1,2,3,4-tetrah ydro-I-naphthyl)butyric acid. From this reaction, only one diastereoisomer was obtained as the principal product. This diastereoisomer could readily be resolved in absolute methyl alcohol by means of brucine into two fractions of diastereoisomeric salts with wide difference in solubility. The less soluble fraction, being the salt of /- y-(6-methoxy-2-carboxy-1,2,3,4-tetrah ydro-1-naphthyl)-butyric acid and brucine, separated out as a crystalline compound. From this fraction of salt, | y-(6-methoxy-2-carboxy-l, 2, 3, 4-tetrahydro-l-naphthyl)-butyric acid was obtained in pure form, while the more soluble fraction, being the salt of d-y -(6-methoxy-2-carboxy-l, 2, 3, 4.tetrahydro-l-naphthyl)-butyric acid and brucine, was obtained as a resinous product after the complete removal of the solvent. From this fraction of salt, d-y -(6-methoxy-2-carboxy-1,2,3,4-tetrahydroI-naphthyl)-butyric acid was obtained in pure form.

2. From the dimethyl ester of /y-(6-methoxy-2-carboxy-l, 2, 3, 4tetrahydro-I-naphthyl)-butyric acid, by means of Dieckmann reaction followed by methylation, a mixture of diastereoisomeric d-\-keto-2-methyl-2-carbomethoxy-7-methoxy-1,2,3,4,9,10,11,12-octahydrophenanthrenes was obtained. From the dimethyl ester of d- y-(6-methoxy-2-carboxy-1,2,3,4-tetrahydro-1-naphthyl)butyric acid, by means of Dieckmann reaction followed by methylation, a mixture of the diastereoisomeric /-1-keto-2-methyl-2-carbomethoxy-/-methoxy-