Scheme 1. (D) in substituents (a)-(d) signifies the asymmetric center to be configuration of the D-amino acid series.Table I. Purity, yields and 'H-NMR spectroscopic data for (7a)-(7d) Comp-Product Yield 'H-NMR (&value, CH,OD, 100 MHz) ound purity [YO] @I 1°4 la1 ~_ _ _ _ _ ~ ~(7a) 84 [c] 54 [c] 0.9 + 1.3 (d, C(CH,),), 3.5 (s, OCH,), 3.85 (m, 5.55 (s, N-CH-CO), 6.5 (q, J=3.2 Hz and 7.2-7.6 (m, Furyl-3+Ph), 7.7 (s, (7b) 70 50 1.2+ 1.4 (d), 3.5 (s), 3.9 (m), 4.15 (s), 5.55 (s), 5.85 (s), 6.55 (q), 6.85 (d), 7.0 (d), 7.2-7.4 (m), 7.6 (d), 7.7 (s) (7c) 80 62 0.9+ 1.3 (d), 3.3 (s), 3.5 (s), 3.85 (m), 4.1 (s), 5.5 (s), 7.2-7.6 (m) [d] (7d) 78 55 0.9+1.3 (d), 1.15 (t), 3.5-3.8 (m. 9H), 4.05 (s), 5.4 (s), 5.5 (s), 7.5 (m) -CHz-CH2-), 4.1 (s, 3-H), 5.5 (s, 5-H), 1.5 Hz, Fuyl-4), 6.85 (d, J=3.2 Hz, Furyl-S), ---CH=N-) [a] Determined by 'H-NMR spectroscopy: the crude products from ( 7 4 -(7d) were contaminated with educt (4, 15, 11, and I OO' , respectively) and with (8) (2, -, 5, and 4%, respectively). [b] Determined by NMR spectroscopy. [c] After recrystallization the purity amounted to 100% and the yield 38%. [d] 250 MHz. Received: May 7, 1981 [Z 845 IE] German version: Angew. Chem. 93. 814 (1981)[I] R .
