A Stereospecific Synthesis of Cantharidin

TABLE

1

CONDENSATION PRODUCTS FROM CINCRONINALDEHYDE AND HETEROCYCLIC REACTIVE METHYL COMPOUNDS ,CH=CI-I-R

CorupoIl!ld .Yn.

R

Heating timp. hr ' I

I

2-Pyridine.CH31

I1 I11 IT'

2-Pyridine.CzH~I 2-Pyridine.n-CaH71 %Pyridine .i-C3H3T

Y

4-Pyridine.CH.il

VI VI1 VI11 IX

4-Pyridine.C>H~I 4-Pyridine.n-C4HgI 2-Quinoline.CHJ 4-Quinoline-CHJ 2-(4-Methylthiazole).CHBI

X

2 2 5 5 2 20 2 2 7 48 2 2 1

Yield, %I

33 (80) 32(88) 65 60 25 90 23 (90) '70 71 70 41 (75) 27 (50) 70

M