Total synthesis of steroidal derivatives. V. The total synthesis of veratrum alkaloids. 1. Verarine

Kutney, James P.; Cable, John; Gladstone, W. A. F.; Hanssen, Harald W.; Torupka, Edward J.; Warnock, William D. C.

doi:10.1021/ja01021a083

Cited by 30 publications

(15 citation statements)

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“…In an alternate reaction sequence [68,98] 111 was diacetylated and converted to the olefin 115, which gave, on catalytic hydrogénation of the A 9(11) -bond, only the 9/?-epimer. Hydroboration of 115 (68%) followed by Birch reduction and dehydration (48%) gave 116, which underwent hydrogénation to give a mixture of 9«-compounds 117 and 118.…”

Section: C-nor-d-homosteroidsmentioning

confidence: 99%

Cd → BCD → Abcd

1974

Organic Chemistry: A Series of Monographs

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The starting CD intermediates for the various total syntheses outlined in this chapter and in Chapter 7 are often the same or quite analogous. Historically, a large effort has been expended in the preparation of such material, both in the context of steroid synthesis and, recently, as a goal unto itself. A discussion of the pathways developed for the synthesis of CD intermediates has been included at this point such that later, when the individual total synthetic schemes are presented, it will be unnecessary to outline the preparation of the starting materials, except in those cases where unique pathways have been developed.Most of the early synthetic plans started with appropriate naphthalene derivatives which in turn gave rise to D-homosteroids. For example, Johnson's estrone synthesis started with decalin-l,5-dione (3, Scheme 12-1) which had earlier been prepared from 1,5-dihydroxynaphthalene (58%) [1], By modifying the previously employed conditions to include Raney nickel hydrogénation at elevated temperatures and pressures in a basic ethanolic solution, it was possible to obtain a mixture of diols, 2 (stereochemistry undetermined), which, without purification, could be oxidized to a mixture of eis and trans diketones 3 [2], The yield for this conversion (l-»3) was 55% and, for synthetic purposes, the mixture 239 O OH J Φ-,ύ^.

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Section: C-nor-d-homosteroidsmentioning

confidence: 99%

Cd → BCD → Abcd

1974

Organic Chemistry: A Series of Monographs

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“…H H O (1) In the presence of a hydrosilane, magnesium oxide catalyzes the conversion of carbonyl compounds to silyl alcohols (eq 2). 2 (2) R 2 CO + (EtO) 3 SiH R 2 CH-OSi(OEt) 3 Aldehydes are converted to alkenes in a biphasic solid-liquid system with magnesium oxide via Wittig-Knoevenagel or Wittig-Horner reactions (eq 3).…”

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confidence: 99%

Magnesium Oxide

Shook¹

2006

Encyclopedia of Reagents for Organic Synthesis

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“…1, were to couple the pyridine system at C17 of the already available 3P-acetoxy-5a-etiojerv-12(13)-en-17-one (1)' and the resultant product 3 could, hopefully by aromatization of ring D (4) and subsequent reduction, lead to the desired 5,6-dihydroverarine (5, R = R' = H) system. It should be noted here that both racemic and optically active forms of 1 are available from total synthesis, the former from our previous work (26,27) and the latter from that of Sondheimer and co-workers (3) who presented a total synthesis of optically active hecogenin from isoandrosterone. For the purposes of the synthetic experiments discussed here we have employed optically active 1 obtained via degradation of hecogenin acetate as outlined in Part I of this series.…”

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confidence: 99%

“…presented in Fig. 1, the readily available (26,27) hydrochrysene derivative 6 was utilized as the model substance and this was condensed with the lithio derivative of 2-ethylpyridine (7).…”

mentioning

confidence: 99%

Synthetic Studies in the Veratrum Alkaloid Series. II. The Total Synthesis of Verarine, Veratramine, Jervine, and Veratrobasine

Kutney¹,

Cable²,

Gladstone³

et al. 1975

Can. J. Chem.

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Coupling of 3β-acetoxy-5α-etiojerv-12(13)-en-17-one (1) with the lithio derivative of 2-ethyl-5-methylpyridine provides the crucial intermediate (3) for the subsequent elaboration to verarine. Aromatization of 3 to 4 and reduction of the latter provides a mixture from which N-acetyl-5α,6-dihydroverarine (11) was isolated. Subsequent introduction of the 5,6-double bond in the latter and removal of the N-acetate function completed the synthesis of verarine (31). In a similar sequence of reactions employing 1 and the lithio derivative of 2-ethyl-3-methoxy-5-methyl-pyridine, the resultant intermediate (54), was elaborated to 5α,6-dihydroveratramine (56). Due to known conversions of the latter to veratramine (14), jervine (32), veratrobasine (33), and 11-deoxojervine (34), the formal total synthesis of these natural products is complete.

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Total synthesis of steroidal derivatives. V. The total synthesis of veratrum alkaloids. 1. Verarine

Cited by 30 publications

References 1 publication

Cd → BCD → Abcd

Cd → BCD → Abcd

Magnesium Oxide

Synthetic Studies in the Veratrum Alkaloid Series. II. The Total Synthesis of Verarine, Veratramine, Jervine, and Veratrobasine

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