Pergamon 0031-9422(94)00542-7 Phytochemistry, Vol. 38, No. 1, pp. 171-174, 1995 Elsevier Science Ltd Printed in Great Britain 0031 9422/95 $9.50 + 0.00 CLERODANE DITERPENOIDS FROM SALVIA UROLEPIS ANA ADELA SANCHEZ, BALDOMERO ESQUIVEL,T. P. RAMAMOORTHY and LYDIARODRIGUEZ-HAHN Instituto de Quimica, Universidad Nacional Aut6noma de M6xico, Circuito Exterior, Ciudad Universitaria, Coyoac~in 04510, M6xico D.F. (Received in revisedform 21 June 1994) Key Word Index--Salvia urolepis; Labiatae; clerodane derivatives; diterpenoids. Abstract--From the aerial parts of Salvia urolepis, three new neoclerodane diterpenoids were isolated. Their structures were determined by spectroscopic means. The known languidulane diterpenoid 2ct-hydroxy-7-epi-8~,17-dihydro- languiduline was also obtained. INTRODUCTION In a continuation of our systematic studies of Mexican Salvia species we have analysed the diterpenoid content of Salvia urolepis, Fern. This species has been classified [1] in section Angulatae, subsection Glumacea (Salvia, subgenus Calosphace), which also includes S. languidula [2-1. A phytochemical study of S. languidula led to the isolation of several diterpenoids with rearranged clero- dane skeletons named languidulane [2-1 and salvilangui- dulane [3]. Diterpenoids with rearranged skeletons of clerodanic origin were also isolated from S. tiliaefolia [4-1 and S. rhyacophila [5-1, two Salvia species included [1-1 in the section Angulatae, subsection Tiliaefolia. In this paper, we describe the isolation and structure determina- tion of the diterpenoids found in S. urolepis. RESULTS AND DISCUSSION The aerial parts of S. urolepis afforded a mixture of oleanolic and ursolic acids, eupatorine [6] (6,7,4'- trimethoxy-5,5'-dihydroxy flavone); 5,6,3'-trihydroxy- 7,4'-dimethoxy flavone [7], the languidulane diterpene 2~-hydroxy-7-epi-8~,17-dihydrolanguiduline (1) pre- viously isolated [8] from S. soussae (Salvia, sect. Poly- stachyae) and named salvisousolide, and three new neo- clerodane diterpenoids whose structures (2-4) were deter- mined by spectroscopic means. The languidulane 1 was the most abundant diterpen- oid. It was obtained as an amorphous powder and identified by comparison of its IR and 1H NMR spectra with those of the previously obtained diterpenoid [8-1. The use of high-field 2D NMR experiments allowed the unambiguous assignment of all the proton resonances (Table 1). The COSY experiments showed a W coupling between H-10 and the Me-20 protons which is only possible in a trans A/B ring fusion of the decalin with the Me-20~-axial. The 13CNMR spectrum of 1, not pre- viously described, was consistent with the languidulane O 3'%,,,'~,7~,,, OAc 1 R I o~",.o / O H ,/o H O / o / ~ o l-.o / 2 R Z R 2 3a, b H,OH O 411, b O H,OH 5 O O structure shown. The carbon resonances (Table 2) of the protonated carbon 5 were assigned by DEPT and HET- COR experiments. The three sp 3 doublets of carbons not bound to oxygen, were unambiguously assigned to C-I, C-8 and C-10. The quaternary and carbonyl carbon signals were established by comparison with the spectra of similar structures [2, 9]. The neoclerodane diterpene 2 was obtained as an unstable oil which showed in its IR spectrum bands due to a hydroxy group (3603 cm- 1), an ~,,fl-unsaturated y- lactone (1772 era-l), an ester function (1738 era-1), an ct, fl-unsaturated ketone (1673 cm -1) and a furan ring (1607, 1560 and 872 cm-1). The mass spectrum was con- sistent with the molecular formula C22H2607 (see experi- mental). A strong peak at m/z 95 (93%) suggested that the ~t,/~-unsaturated ketone group was at C-12 [10]. The 171