Browsing by Author "Yogesh Kumar Gupta"

Now showing 1 - 4 of 4

23-Hydroxyphysalolactone, a New Withanolide with a 23-Hydroxyl Group from Physalis peruviana (Solanaceae)
(1988) Tadashi Eguchi; Nobuo Ikekawa; Yoshinori Fujimoto; Katsumi Kakinuma; Mahendra Sahai; Munna Prasad Verma; Yogesh Kumar Gupta
A new withanolide having a hydroxyl group at the C-23 position has been isolated from the leaves of Physalis peruviana. The structure of this withanolide has been established to be (20S,22R,23R)-6α-chloro-4β,5β, 14α, 17β,20,2 3-hexahydroxy-1-oxowitha-2,24-dienolide (by spectroscopic evidence. © 1988, The Pharmaceutical Society of Japan. All rights reserved.
Annonaceous Acetogenins from the Seeds of Annona squamosa. Adjacent Bis-tetrahydrofuranic Acetogenins
(1994) Mahendra Sahai; Sanjewon Singh; Manorama Singh; Yogesh Kumar Gupta; Satoko Akashi; Reiko Yuji; Kazuo Hirayama; Hitomi Asaki; Hiroshi Araya; Noriyuki Hara; Tadashi Eguchi; Katsumi Kakinuma; Yoshinori Fujimoto
The petroleum ether extract of the seeds of Annona squamosa L. yielded thirteen adjacent and four non-adjacent bis-tetrahydrofuranic acetogenins, in addition to squamocin (1) and squamostatin-A. The structures of the thirteen acetogenins, named as squamocins-B (2), -C (3), -D (4), -E (5), -F (6), -G (7), -H (8), -I (9), -J (10), -K (11), -L (12), -M (13) and -N (14), have been established on the basis of spectral evidence. Squamocins-B, -D, -E, -F, -I, -K and -N are new acetogenins. The structures of these acetogenins vary in the carbon number (C37 or C35), the number and position of hydroxyl groups (substituted at C-4, C-12, C-28 or C-29) and the stereochemistry at the bis-tetrahydrofuran moiety. Squamocin-N (14) has an unprecedented threo-cis-threo-cis-threo stereochemistry in its bis-tetrahydrofuran portion. Co-occurrence of a diastereoisomeric pair, 9 and 10, is noteworthy. © 1994, The Pharmaceutical Society of Japan. All rights reserved.
Clerodane and ent-halimane diterpenes from polyalthia longifolia
(1995) Noriyuki Hara; Hitomi Asaki; Yoshinori Fujimoto; Yogesh Kumar Gupta; Ashish Kumar Singh; Mahendra Sahai
A hexane extract of the stem bark of Polyalthia longifolia furnished nine new clerodane and ent-halimane diterpenes, i.e. 16-hydroxycleroda-4(18),13-dien-16,15-olide, 16-oxocleroda-4(18),13E-dien-15-oic acid, cleroda-4(18),-13-dien-16,15-olide, 16-hydroxy-ent-halima-5(10),13-dien-16,15-olide, 16-oxo-ent-halima-5(10),13E-dien-15-oic acid, ent-halima-1(10),13E-dien-16,15-olide, 16-oxo-ent-halima-5(10),13E-dien-15-oic acid, ent-halima-5(10),13-dien-16,15-olide and ent-halima-5(10),13E-dien-16,15-olide, along with five known clerodane diterpenes. The structures of these compounds were elucidated by spectroscopic methods. The 13E configuration of two of the new ent-halimanes and one of the known clerodanes was firmly established by NOE experiments. © 1995.
Squamocin, a New Cytotoxic Bis-tetrahydrofuran Containing Acetogenin from Annona squamosa
(1988) Yoshinori Fujimoto; Tadashi Eguchi; Katsumi Kakinuma; Nobuo Ikekawa; Mahendra Sahai; Yogesh Kumar Gupta; Tadashi Eguchi
Squamocin, a new trihydroxy-bis-tetrahydrofuran fatty acid γ-lactone (acetogenin), has been isolated from Annona squamosa L. (Annonaceae) and its structure has been elucidated on the basis of spectral evidence and chemical degradations. © 1988, The Pharmaceutical Society of Japan. All rights reserved.