Continuing the separation of the total alkaloids of Buxus sempervirens L. cultivated in the environs of Kobuleti, Adzhar ASSR [i], we have isolated a new alkaloid which has been named cyclovirobuxine-F and has the composition C=eH46N20 (I), mp 224-226°C (ethanol), [a] D + 52.71 ° (c 0.702~ chloroform).The IR spectrum of (I) showed absorption bands at (cm-*) 3310, 3050, 1460 (OH, methylene of a cyclopropane ring); 1642, 1592 (--NH2 group)[2]. The NMR spectrum of (I) exhibited resonance signals in the form of singlets at (ppm) 0.71, 0.76, 0.88, 0.94 (12 H, CH3), and 2.23 [6H, N(CH3)2]; and in the form of doublets at 0.g9 (3H, CH~, J = 2 H) and 4.06 (m, 1 H, --CH-- OH). The mass spectrum of alkaloid (I) had the main peaks of ions with m/z 71, 72 (100%), 84, 386, 371, and 402 (M+).The peak of the ion with m/z 72, the maximum in the mass spectrum, arises as the result of the cleavage of the bond between C17 and C2o and confirms the presence of a dimethylamino group in the C2o position of the pregnane nucleus [3, 4].The acetylation of (I) with acetic anhydride in pyridine formed N,O-diacetylcyclovirobuxine-F, with the composition C3oHsoN203 (II), mp 229-231°C (acetone~etroleum ether (i~3)), [a]D --39"61° (c 0.807; chloroform).In the IR spectrum of (II), the absorption bands of the hydroxy and primary amino group had disappeared but absorption bands had appeared at (cm -I) 1742 (0-acetyl) and 1636 (N-acetyl).The NMR spectrum of (II) showed signals at (ppm) 0.80, 0.81 (s, 6 H, CH3), 0.83 (s, 6 H, CH3), 0.94 (d, 3 H, CH3), 2.05 (s, 3 H, N-acetyl), 2.28 [s, 6 H, N(CHs)2], and 4.94 (m, 1 H, -HC-O-acetyl). In the mass spectrum of (II) the main peaks were those of ions with m/z 70, 71, 72, (I00%), 84, i00, 314, 386, 451, and 486 (M+).The Hess methylation of (I) led to a N-dimethyl derivative with the composition C28HhoN20 (III), mp 224-246°C (ethanol), [e]D + 42"5° (c 0.901; chloroform) M + 430.The N-dimethyl derivative (III) was identified by means of a mixed melting point and also from its IR, NMR, and mass spectra as N,N'-dimethylcyclovirobuxine-D [5-10].Consequently, cyclovirobuxine-F (I) has the structure and configuration of 38-amino-20-~ dimethylamino-16~-hydroxy-4,4',14~-trimethyl-98,19-cyclo-5~-pregnane.