The invention pertains to the synthesis of carbamate and urea compounds. In particular the invention is directed to the synthesis of carbamate and urea compounds which may be used in the production of compounds that are used to stabilize nitrocellulose. The method of the invention comprises preparing a carbamate or urea derivative comprising reacting an amine and a carbonate or carbamate in the presence of an ionic liquid.

Provided are processes for the preparation of (S)-tert-butyl 4,5-diamino-5-oxopentanoate, or a salt, solvate, hydrate, enantiomer, mixture of enantiomers, or isotopologue thereof. Also provided are solid forms of various intermediates and products obtained from the processes.

Provided are processes for the preparation of (S)-tert-butyl 4,5-diamino-5-oxopentanoate, or a salt, solvate, hydrate, enantiomer, mixture of enantiomers, or isotopologue thereof. Also provided are solid forms of various intermediates and products obtained from the processes.

Provided are processes for the preparation of (S)-tert-butyl 4,5-diamino-5-oxopentanoate, or a salt, solvate, hydrate, enantiomer, mixture of enantiomers, or isotopologue thereof. Also provided are solid forms of various intermediates and products obtained from the processes.

Provided are processes for the preparation of (S)-tert-butyl 4,5-diamino-5-oxopentanoate, or a salt, solvate, hydrate, enantiomer, mixture of enantiomers, or isotopologue thereof. Also provided are solid forms of various intermediates and products obtained from the processes.

The use of ionic liquids as a solvent for chemoselective bioconjugation reactions is described. For example, methods of preparing bioconjugates in ionic liquids via a phosphine-mediated azide-amine reaction to form a urea linkage between a biomolecule substrate and a second molecule are described. Methods of preparing bioconjugates with amide or enamine linkages in ionic liquids are also described. The methods can be used to prepare tagged biomolecules, such as dye-tagged proteins, peptides, nucleic acids, or saccharides (e.g., aminosaccharides), for use in various applications; to form biomolecule-polymer conjugates; or to form biomolecule-therapeutic agent conjugates, such as antibody-drug conjugates.

The present invention provides a process of producing a trifluoromethoxylated aryl or trifluoromethoxylated heteroaryl having the structure:

##STR00001##

wherein A is an aryl or heteroaryl, each with or without subsutitution; and R.sub.1 is —H, -(alkyl), -(alkenyl), -(alkynyl), -(aryl), -(heteroaryl), -(alkylaryl), -(alkylheteroaryl), —NH-(alkyl), —N(alkyl).sub.7, —NH-(alkenyl), —NH-(alkynyl) —NH-(aryl), —NH-(heteroaryl), —O-(alkyl), —O-(alkenyl), —O-(alkynyl), —O-(aryl), —O-(heteroaryl), —S-(alkyl), —S-(alkenyl), —S-(alkynyl), —S-(aryl), or —S-(heteroaryl), comprising: (a) reacting a compound having the structure:

##STR00002##

with a trifluoromethylating agent in the presence of a base in a first suitable solvent under conditions to produce a compound having the structure:

##STR00003##

and (b) maintaining the compound produced in step (a) in a second suitable solvent under conditions sufficient to produce the trifluoromethoxylated aryl or trifluormethoxylated heteroaryl having the structure:

##STR00004##

The present invention provides a process of producing a trifluoromethoxylated aryl or trifluoromethoxylated heteroaryl having the structure:

##STR00001##

wherein A is an aryl or heteroaryl, each with or without subsutitution; and R.sub.1 is —H, -(alkyl), -(alkenyl), -(alkynyl), -(aryl), -(heteroaryl), -(alkylaryl), -(alkylheteroaryl), —NH-(alkyl), —N(alkyl).sub.7, —NH-(alkenyl), —NH-(alkynyl) —NH-(aryl), —NH-(heteroaryl), —O-(alkyl), —O-(alkenyl), —O-(alkynyl), —O-(aryl), —O-(heteroaryl), —S-(alkyl), —S-(alkenyl), —S-(alkynyl), —S-(aryl), or —S-(heteroaryl), comprising: (a) reacting a compound having the structure:

##STR00002##

with a trifluoromethylating agent in the presence of a base in a first suitable solvent under conditions to produce a compound having the structure:

##STR00003##

and (b) maintaining the compound produced in step (a) in a second suitable solvent under conditions sufficient to produce the trifluoromethoxylated aryl or trifluormethoxylated heteroaryl having the structure:

##STR00004##

Carmustine may be safely and efficiently produced by reacting 2-chloroethylamine hydrochloride and 1,1′-carbonyldiimidazole to afford 1,3-bis(2-chloroethyl)-1-urea, followed by nitrosation to give the final product.

Carmustine may be safely and efficiently produced by reacting 2-chloroethylamine hydrochloride and 1,1′-carbonyldiimidazole to afford 1,3-bis(2-chloroethyl)-1-urea, followed by nitrosation to give the final product.