- Further development of the tin-catalyzed transcarbamoylation reaction
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Studies carried out to further develop tin-catalyzed trans-carbamoylation reactions demonstrated that transcarbamoylation of cinnamyl alcohol in the context of allyl cyanate-to-isocyanate rearrangement can be efficiently carried out on a ten-gram scale and that tin-catalyzed transcarbamoylation is a valuable alternative to the method using trichloroacetyl isocyanate. In addition, methyl carbamate was found to be an economical carabamoyl donor in tin-catalyzed transcarbamoylation, which showed broad functional group tolerance and allowed a streamlined workup procedure. Finally, a unique synthetic method was developed for the preparation of carbamate-tethered terpene glycoconjugates.
- Hasegawa, Tomoyuki,Ichikawa, Yoshiyasu,Masuda, Toshiya,Minami, Takahiro,Morishita, Yukinori,Ochi, Rika,Sato, Hiroshi
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p. 2373 - 2378
(2020/08/19)
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- An efficient synthesis of carbamates by tin-catalyzed transcarbamoylation reactions of primary and secondary alcohols
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A new approach to the synthesis of carbamates based on a tin-catalyzed transcarbamoylation process has been developed. Reactions of primary and secondary alcohols with phenyl carbamate in toluene at 90 ° C proceed smoothly in the presence of tin-catalyst to generate the corresponding carbamates in good yields. This mild method exhibits a broad functional-group tolerance. Georg Thieme Verlag Stuttgart.
- Ichikawa, Yoshiyasu,Morishita, Yukinori,Kusaba, Shuhei,Sakiyama, Naoto,Matsuda, Yasunori,Nakano, Keiji,Kotsuki, Hiyoshizo
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experimental part
p. 1815 - 1818
(2010/10/05)
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- Neutral hosts for the complexation of creatinine
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Three hydrogen bonds are formed between creatinine and derivatives of 2-amino-4(3H)pyrimidone. Changes in the tautomer ratio of the latter upon complexation can be observed by UV spectroscopy. The formation of a further hydrogen bond between creatinine and a 4-aminoacridin-5-yl-amino-substituted 4(3H)pyrimidone seems to be sterically prevented. The properties of three other, quite different compounds assumed to form three hydrogen bonds with creatinine have also been investigated. Dodecyl 4-octadecylallophanate and 2,6-bis(dodecylamino)-pyridine do not associate appreciably with creatinine, which can be explained by the formation of an intramolecular hydrogen bond in the former compound and the lack of tautomerization of the latter. With 6-(1-heptyloctylamino)-2(1H)-pyridone, however, creatinine forms a complex that is almost as stable as those with 2-amino-4(3H)-pyrimidone derivatives.
- Buhlmann,Simon
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p. 7627 - 7636
(2007/10/02)
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