The present invention provides a new process for preparation of imidazo-tetrazine class of chemical entity useful as anticancer agent. The present invention provides a commercially and economically viable process for preparation of Temozolomide of formula (VI).

##STR00001##

Present invention also relates to an intermediate compound of formula (III) and its preparation useful in the process for preparing Temozolomide.

##STR00002##

The present invention provides a new process for preparation of imidazo-tetrazine class of chemical entity useful as anticancer agent. The present invention provides a commercially and economically viable process for preparation of Temozolomide of formula (VI).

##STR00001##

Present invention also relates to an intermediate compound of formula (III) and its preparation useful in the process for preparing Temozolomide.

##STR00002##

The present invention provides a new process for preparation of imidazo-tetrazine class of chemical entity useful as anticancer agent. The present invention provides a commercially and economically viable process for preparation of Temozolomide of formula (VI). ##STR00001## Present invention also relates to an intermediate compound of formula (III) and its preparation useful in the process for preparing Temozolomide. ##STR00002##

The present invention provides a new process for preparation of imidazo-tetrazine class of chemical entity useful as anticancer agent. The present invention provides a commercially and economically viable process for preparation of Temozolomide of formula (VI). ##STR00001## Present invention also relates to an intermediate compound of formula (III) and its preparation useful in the process for preparing Temozolomide. ##STR00002##

Monoisocyanate impurities are removed from a process stream obtained when solvent is separated from a polyisocyanate product. The monoisocyanates are reacted with amine compounds at specific molar ratios to produce ureas. The ureas can be discarded by burning, landfilling or otherwise. Alternatively the ureas can be recycled back into the polyisocyanate manufacturing process, where they are formed into biuret compounds that can remain with the polyisocyanate product.

Monoisocyanate impurities are removed from a process stream obtained when solvent is separated from a polyisocyanate product. The monoisocyanates are reacted with amine compounds at specific molar ratios to produce ureas. The ureas can be discarded by burning, landfilling or otherwise. Alternatively the ureas can be recycled back into the polyisocyanate manufacturing process, where they are formed into biuret compounds that can remain with the polyisocyanate product.

Monoisocyanate impurities are removed from a process stream obtained when solvent is separated from a polyisocyanate product. The monoisocyanates are reacted with amine compounds at specific molar ratios to produce ureas. The ureas can be discarded by burning, landfilling or otherwise. Alternatively the ureas can be recycled back into the polyisocyanate manufacturing process, where they are formed into biuret compounds that can remain with the polyisocyanate product.

Monoisocyanate impurities are removed from a process stream obtained when solvent is separated from a polyisocyanate product. The monoisocyanates are reacted with amine compounds at specific molar ratios to produce ureas. The ureas can be discarded by burning, landfilling or otherwise. Alternatively the ureas can be recycled back into the polyisocyanate manufacturing process, where they are formed into biuret compounds that can remain with the polyisocyanate product.