37905-02-5Relevant articles and documents
New approach to the steroid BCD-ring system using tandem radical cyclization
Takahashi, Takashi,Tomida, Satoshi,Sakamoto, Yasuharu,Yamada, Haruo
, p. 1912 - 1913 (1997)
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INTERACTION OF TERMINAL EPOXIDES OF α-GERANYL AND α-FARNESYL ACETATES WITH FLUOROSULFONIC ACID
Ungur, N. D.,Popa, N. P.,Kul'chitskii, V. N.,Vlad, P. F.
, p. 618 - 621 (1993)
The interaction of 7,8-epoxygeranyl acetate and 11,12-epoxy-E,E-farnesyl acetate with fluorosulfonic acid forms products of the opening of the epoxide ring.
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Grieco,P.A.
, p. 486 - 487 (1972)
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Synergistic factors ensue high expediency in the synthesis of menaquinone [K2] analogue MK-6: Application to access an efficient one-pot protocol to MK-9
Yerramsetti, Nanaji,Dampanaboina, Lavanya,Mendu, Venugopal,Battula, Satyanarayana
, (2020/11/12)
Here we report a practical and efficient method for the synthesis of menaquinone vitamin (K2) analog MK-6 in all trans forms through “1 + 5 convergent synthetic approach” of pentaprenyl chloride with monoprenyl menadione derivative. In the synergistic factors, less efficient leaving group/more efficient nucleophile (Cl) in the substrate makes it more prominent reaction by eliminating all Sn2’ side reaction products. Further, the addition of acetic acid in the last step (desulfonation) of reaction sequence removes the limitations of the reactions in terms of cyclized side product (multiple reactions of pentaprenyl alcohol with Et3B), byproduct (Et3B, incendiary compound) formations and their interruption in the tricky purification processes. The utility of this method was further extended to find an efficient one-pot synthesis to MK-9 to the gram scale synthesis. This approach is economical and efficient and avoids the awkward chromatographic separation processes.
Structure-Odor Relationship Study on Geraniol, Nerol, and Their Synthesized Oxygenated Derivatives
Elsharif, Shaimaa Awadain,Buettner, Andrea
, p. 2324 - 2333 (2018/03/21)
Despite being isomers having the same citrus-like, floral odor, geraniol, 1, and nerol, 3, show different odor thresholds. To date, no systematic studies are at hand elucidating the structural features required for their specific odor properties. Therefore, starting from these two basic structures and their corresponding esters, namely, geranyl acetate, 2, and neryl acetate, 4, a total of 12 oxygenated compounds were synthesized and characterized regarding retention indices (RI), mass spectrometric (MS), and nuclear magnetic resonance (NMR) data. All compounds were individually tested for their odor qualities and odor thresholds in air (OT). Geraniol, the Z-isomer, with an OT of 14 ng/L, was found to be more potent than its E-isomer, nerol, which has an OT of 60 ng/L. However, 8-oxoneryl acetate was the most potent derivative within this study, exhibiting an OT of 8.8 ng/L, whereas 8-oxonerol was the least potent with an OT of 493 ng/L. Interestingly, the 8-oxo derivatives smell musty and fatty, whereas the 8-hydroxy derivatives show odor impressions similar to those of 1 and 3. 8-Carboxygeraniol was found to be odorless, whereas its E-isomer, 8-carboxynerol, showed fatty, waxy, and greasy impressions. Overall, we observed that oxygenation on C-8 affects mainly the odor quality, whereas the E/Z position of the functional group on C-1 affects the odor potency.
Synthesis of Cembranoid Analogues through Ring-Closing Metathesis of Terpenoid Precursors: A Challenge Regarding Ring-Size Selectivity
Heidt, Tanja,Baro, Angelika,K?hn, Andreas,Laschat, Sabine
, p. 12396 - 12404 (2015/08/25)
A systematic study on ring-closing metathesis with Grubbs II catalyst to cembranoid macrocycles is described. Acyclic terpenoids with a functional group X in the homoallylic position relative to an RCM active terminus and substituents R, R1 directly attached to the other terminal double bond were prepared from geraniol derived trienes and fragments that are based on bromoalkenes and dimethyl malonate. Such terpenoids were suitable precursors, despite the presence of competing double bonds in their framework. The size of R and R1 is crucial for successful macrocyclization. Whereas small alkyl substituents at the double bond directed the RCM towards six-membered ring formation, cross metathesis leading to dimers dominated for bulkier alkyl groups. A similar result was obtained for precursors without functional group X. In the case of unsymmetrically substituted terpenoid precursor (R=Et, R1=Me) with homoallylic OTBS or OMe group, the RCM could be controlled towards formation of macrocyclic cembranoids, which were isolated with excellent E-selectivity. The role of the substituents was further studied by quantum chemical calculations of simplified model substrates. Based on these results a mechanistic rationale is proposed.
