Amide functional group structural formula

Tautomerism is common in pteridine derivatives and the favored tautomers should be represented by the structural formulas. Amino groups exist as such and not in the iminodihydro form whereas the hydroxy and thiol functions 9 located adjacent or para to a ring nitrogen atom prefer the thermodynamically more stable amide (lactam) and thioamide (thioxo) configuration 8 (Scheme 1) . 

The name erythrinine had been assigned to an alkaloid isolated in 1969 from E. lithosperma (61). The formula for this alkaloid was found to be C30H36N4O5, and little structural information was known except that it contained four methoxyl groups and one amide function and that all four nitrogen atoms were present in rings. No further elaboration of the structure has been reported. 

The functional group created when the —OH of a carboxyl group is replaced by an NH group is called an amide (Section 1.3F). Draw the structural formula of acetamide, which is derived from acetic acid, and determine whether proton transfer to the amide group from HCl occurs preferentially on the amide o>ygen or the amide nitrogen. 

D Write, recognize, or otherwise identify (a) the structural unit, or functional group, (b) the general formula, and (c) the molecular or structural formulas and/or names of specific examples of the following classes of organic compounds alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, ethers, aldehydes, ketones, carboxylic acids, esters, amines, and amides. 

Identify the structural formulas of the functional groups that distinguish amines and amides. 

The (+)-13a-hydroxyaphyllidine structure was proposed on the basis of the C15H22N2O2 molecular formula determined by HRMS, IR absorptions at 3270, 1635 and 1560 cm (suggesting the presence of hydroxyl, lactam and ethylene functions), and also of the UV spectrum which indicates a vinyl amide group (A ax 239 nm). The position of the hydroxyl group was assessed by comparison of the C NMR data of (+)-13a-hydroxyaphyllidine and aphyllidine, which showed similar resonances for the carbon atoms of rings A, B, and C, and also by... 

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