Fragmented compounds

Compound A, C/H, was found to be optically active. On catalytic reductior over a palladium catalyst, 2 equivalents of hydrogen were absorbed, yielding compound B, CyH. On ozonolysis of A, two fragments were obtained. One fragment was identified as acetic acid. The other fragment, compound C, wa an optically active carboxylic acid, C5Hl002- Write the reactions, and drav structures for A. B and C. 

The only publication on the angularly condensed benzologues, pyrimido[2,l-tf]quinoxalines, describes the synthesis of 161 by formation of both the pyrimido and the pyrazino ring from [6+0] atom fragments. Compound 160, the targeted cyclocondensation product of the propanediamine derivative 159, spontaneously cyclized to the pyri-mido[2,l- ]quinoxaline A-oxide 161 (Equation 17) <2002S2687>. 

Compounds with P—C—N—B fragments Compounds containing the P—C—N—B fragment can be obtained in the borylation reactions of functionally substituted phosphines with boranes (88IZV2190 89IZV1375). As a rule, the first stage is characterized by the formation of complexes in all cases. 

Provided that the compounds analysed in positive mode are not known, the selected and fragmented compound ions (cf. Fig. 2.5.7(b)—(d)) after computer aided product ion library search were described as AE (Fig. 2.5.7(b) and (c)) and polyglycol amines... 

Fig. 9. X-ray structure of a molecular basket containing two benzylaza crown ether fragments (compound 18). (Reproduced with permission from the Royal Netherlands Chemical Society)...

Taylor, J. D., Gilbert, P J., Williams, M. A., Pitt, W. R., and Ladbury, J. E. (2007). Identification of novel fragment compounds targeted against the pY pocket of v-Src SH2 by computational and NMR screening and thermodynamic evaluation. Proteins Structure Function and Bioinformatics 67, 981-990. 

Additional study uncovered further elaboration in the form of compounds, such as 9 to 11, from the reaction of glucose with methylammonium acetate.171 Compound 9 is yellow-orange, 11 (the structure of which is not certain) is yellow (11a, Amax = 352 nm lib, Amax = 354 nm), and 10 has Amax = 406 nm. It should be noted that 9 has a C8 chain, which must be the result of the cleavage of the C6 chain of glucose, followed by a recombination of fragments. Compound 10 may be formed similarly, but the pathway to 11 has not been clarified. 

Dinitrogen is the classic example of a naked E2 fragment. The triple-bonded analogues for the heavier congeners are observed only in the gas phase, but have been stabilized by bonding to metal fragments. Compounds... 

Scheme 6 Rapid Route to Protected Fragments (Compound 21 Results from Quenching of Excess HOBt Ester)l l Fmoc—Xaa —OH + PyBOP + DIPEA...

Fig. 6 Superposition of initial fragment (compound 12, light blue) and final compound AT9283 (dark blue) bound to Aurora A...

Fig. 3 Details of the crystal structures of the active site (see legend to Fig. lc) and selected solvent molecules for fragment compounds 12, 13, 14 and 15 binding to Nt-Hsp90. The by a compound number indicates it came from the second round of fragment screening (see text)...

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