Template-assisted photodimerization of N-unprotected uracil derivatives: selective formation of the cis-syn photodimer.
نویسندگان
چکیده
A UV light-induced photodimerization of 5-[(imidazol-1-yl)methyl]uracil using glutamate- and aspartate-derived cyclic dipeptides (2,5-diketopiperazines - DKPs) as templates was investigated. Dual salt bridge formation between imidazole side chains and carboxylic acids resulted in the preorganization of the uracil monomers and the preferential formation of the cis-syn photodimer.
منابع مشابه
Even-odd alternation in mass spectrum of thymine and uracil clusters: evidence of intracluster photodimerization.
Multiphoton ionization of thymine and uracil clusters generated by a supersonic molecular beam gave rise to a remarkable alternation of mass spectral intensities between even- and odd-numbered clusters. Such alternation was observed in clusters of up to 30 molecules. Excitation to the two lowest electronically excited states seemed to be a strong prerequisite. In view of the well known photodim...
متن کاملCyclobutane thymine dimers in a ras proto-oncogene hot spot activate the gene by point mutation.
ras proto-oncogenes with a cyclobutane-type thymine photodimer (cis-syn or trans-syn isomer) were constructed by replacement of a portion of the gene with a chemically synthesized fragment. When the genes were transfected by the calcium phosphate method into mouse NIH3T3 cells, they induced focus-formation, indicating that both photoproducts were mutagenic in mammalian cells. Sequence analysis ...
متن کاملThe synthesis of Beta-Carbonhomologous Intermediate of Norcardicin A. A General Method for Selective Preparation of The Beta-Lactam Ring in the Presence of Free Phenolic Hydroxyl Groups
The synthesis of cis-N-[a-carbobenzyloxy-b-(p-hydroxyphenyl)ethyl]-3-phthalimido-4-styryl-2-azetidinone is described. We have found that the electron-rich Schiff bases can afford the cis-b-lactam ring even in the presence of the free hydroxyl functions. The mechanisms of cis and trans-b-lactam ring formation are discuss...
متن کاملSite-directed regiocontrolled synthesis of a 'head-to-head' photodimer via a single-crystal-to-single-crystal transformation involving a linear template.
Co-crystallisation of 1,8-naphthalenedicarboxylic acid (1,8-nap) with trans-1-(3-pyridyl)-2-(4-pyridyl)ethylene (3,4-bpe) gives a discrete molecular solid-state assembly, 2(3,4-bpe).2(1,8-nap) 1, that is held together by four O-H...N hydrogen bonds wherein the diacid directs a regiocontrolled [2 + 2] photodimerization; the reaction occurs by way of a single-crystal-to-single-crystal transformat...
متن کامل0108 - 7681 Photodimerization of the a 0 - polymorph of ortho - ethoxy - trans - cinnamic acid in the solid state . I . Monitoring the reaction at 293 K
polymorph of ortho-ethoxy-trans-cinnamic acid in the solid state. I. Structural changes that occur during the [2 + 2] photodimer-ization of the metastable H-polymorph of ortho-ethoxy-trans-cinnamic acid at 293 K are presented here. Crystals of the H-polymorph were ®rst stabilized by exposing the-polymorph to UV light for a short period of time at 343 K. The photodimerization reaction was then c...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Chemical communications
دوره 53 69 شماره
صفحات -
تاریخ انتشار 2017