Several of the members of the series are good candidates for in vivo inhibition of leukotriene biosynthesis, including the sulfoxide, sulfone, and amide derivatives indicated. These compounds obviously are not susceptible to incorporation into phospholipid. Clearly, the RBL-1 5-lipoxygenase does not demand that the carboxyl surrogate be an anionic group.16 (15) The amide of 1 was prepared by ammonolysis of the methyl ester; all other carboxyl replacement analogues were synthesized from bromoacetylene 10 (undeuterated) by standard methods. Each of the analogues in the series listed here has the structure in which the group indicated replaces the COOH group of 1.

Acknowledgment. We express our appreciation to Dr. U. Weiss for valuable discussions.Registry No. (S)-(-)-2a, 65915-63-1; (S)-(-)-2b, 84580-10-9;(S)-(-)-3, 84499-95-6; (±)-4a, 79605-67-7; (S)-(-)-4a, 84580-11-0; (S)-(-)-4a camphanate, 84520-47-8; (S)-(-)-4b, 78341-38-5; 5, 6786-30-7; (S)-(-)-6a, 84499-96-7; (S)-(-)-6b, 84499-97-8; (S)-(-)-7, 55095-00-6; 8, 829-14-1; (S)-(-)-9a, 84499-98-9; (S)-(-)-9b, 84499-99-0; (fi)-(+)-10,84500-00-5; (S)-(-)-10,84500-01-6; (±)-lla, 62249-35-8; (fi)-(-)-lla, 62210-83-7; (fi)-H-lla camphanate, 84580-12-1; (R)-(-)-llb, 84580-13-2; benzocyclohepten-3-one, 826-73-3.

mixtures were incubated at 37 °C for 16 h and were periodically analyzed by LVE followed by ninhydrin visualization of the unreacted amino acid. See Table III for specific results.

0.075 g, 0.18 mmol) was trichloroacetylated as above to yield pure cis complex in 97% yield following column chromatography, eluting with 5% ether/petroleum ether: IR (CS2) 2100, 2060, 2040 cm"1 (metal carbonyl), 1770 cm'1 (OCOCCl3); 1H NMR (CS2) 6.1 (s, 1 H, complexed acetylenic), 4.7 (br m, w1/2 = 12 Hz, CHOH), 1.7-2.22 (br m, 9 H, ring + OH).Acknowledgment. We are grateful for financial support provided by the Public Health Service (GM 26760).

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