In the search of new biologically active compounds and in continuation of our investigation on the
synthesis of nitrogen-containing drimane and homodrimane sesquiterpenoids 1-3, we herein describe the
preparation of iso-drimenoic acid amides (7a-c) from norambreinolide (1), according to the scheme given
below.

Reagents and conditions: a) P2O5, DMSO, CH2Cl2, 20°C, 40 min, Et3N, 20°C, 40 min, 93%; b) NaClO2,
NaH2PO4, t-Bu-OH, 2-Me-2-butene, H2O, 20°C, 2 h, 94%; c) (COCl)2, C6H6, 20°C, 1 h, △, 1 h, 95%; d)
R-NH2 (6a-c), CH2Cl2, 20°C, 24 h, △, 10 h.
Starting drimenoic acid (4) for the preparation of amides (7a-c) was synthesized from norambreinolide
(1) in the six-steps synthesis with an overall yield 55%. The reaction of acid (4) with (COCl)2 produced
acid chloride (5), reactions of which with 2-amino-pyrimidine (6a), 4-amino-pyrimidine (6b) and 2-
amino-pyrazine (6c) formed amides (7a-c).
The structures of amides (7a-c) were established on the basis of their IR, 1H – NMR, 13C – NMR, 15N –
NMR, and mass – spectral data. It is very likely that acid chloride (5) is formed as a result of the
migration of a double bond △7(8) in acid (4) to △8(9) in acid chloride (5) in the reaction conditions.
The newly synthesized amides (7a-c) are of a scientific and practical importance as compounds with a
potential biological activity.
1. K. Kuchkova, A. Aricu, E. Secara, A. Barba, P. Vlad, N. Ungur, C. Tuchilus, S. Shova, Gh.
Zbancioc, I.I. Mangalagiu, Med. Chem. Res., 2014, 23, 1559-1568.
2. K.I. Kuchkova, A.N. Aricu, E.S. Secara, A.N. Barba, P.F. Vlad, F.Z. Makaev, E. Melnic, V.Kh.
Kravtsov, Chem. Nat. Compd., 2015, 51, 684-688.
3. A.N. Aricu, K.I. Kuchkova, A.N. Barba, I.P. Dragalin, S. Shova, N. Vornicu, E.K. Gorinchoi,
E.S. Sekara, L.V. Lungu, M. Niculaua, N.D. Ungur, P.F. Vlad, Chem. Nat. Compd., 2016, 52,
1029-1036.
4. K.I. Kuchkova, Y.M. Chumakov, Y.A. Simonov, G. Bocelli, A.A. Panasenko, P.F. Vlad,
Synthesis, 1997, №9, 1045-1048.
5. K.I. Kuchkova, A.N. Aricu, I.P. Dragalin, P.F. Vlad, Khim. Prir. Soedin., 2005, №2, 152-155.