We claim:

1. A compound of the formula:

2. A compound of the formula:

3. A method of preparing a compound of the formula:

comprising the steps of:

hydrolyzing diacetyl-acyclovir to acyclovir in the presence of potassium

hydroxide; and

simultaneously forming a potassium salt of acyclovir.

4. The method of claim 3 wherein the step of hydrolyzing the diacetyl-acyclovir to

acyclovir in the presence of potassium hydroxide further comprises the step of maintaining the reaction temperature at approximately 18° to 22°C.

5. The method of claim 4 wherein the diacetyl-acyclovir is washed with an alcohol prior

to hydrolysis to remove impurities.

6. A method of preparing a compound ofthe formula:

comprising the steps of: adding an alcohol to a vessel;

adding diacetyl-acyclovir to the vessel;

adding potassium hydroxide to the vessel to form a reaction mixture;

keeping the reaction mixture at approximately 18° to 22°C;

heating the reaction mixture;

adding additional potassium hydroxide to the reaction mixture;

stirring the reaction mixture;

adding additional potassium hydroxide to the reaction mixture;

refluxing the reaction mixture;

cooling the reaction mixture;

collecting product by filtration; and

washing the product.

7. The method of claim 6 wherein the step of adding an alcohol to a vessel further

comprises adding an alcohol selected from the group containing ethanol, methanol and a

mixture of ethanol and methanol.

8. The method of claim 7 wherein said alcohol comprises anhydrous methanol.

9. The method of claim 6 wherein the step of adding the potassium hydroxide to the

vessel precedes the step of adding the diacetyl-acyclovir to the vessel.

10. The method of claim 6 wherein the step of adding additional potassium hydroxide to

the reaction mixture is combined with the step of adding potassium hydroxide to the vessel so that all the potassium hydroxide is added in one step.

1 1. A method of preparing substantially purified acyclovir comprising the steps of:

hydrolyzing diacetyl-acyclovir in the presence of potassium hydroxide and

simultaneously forming an acyclovir potassium salt;

maintaining the hydrolysis reaction at approximately 18° to 22°C; and

converting the acyclovir potassium salt to substantially purified acyclovir in the presence of an acid.

12. A method of preparing substantially purified acyclovir comprising the steps of:

alkylating diacetyl-guanine to form diacetyl-acyclovir;

hydrolyzing the diacetyl-acyclovir in the presence of potassium hydroxide to form

an acyclovir potassium salt; and

crystallizing the substantially purified acyclovir from water in the presence of an acid.

13. The method of claim 12 further comprising the step of washing the diacetyl-acyclovir

to remove impurities.

14. The method of claim 13 wherein the step of washing the diacetyl-acyclovir to remove

impurities further includes washing the diacetyl-acyclovir with an alcohol.

15. The method of claim 14 wherein the alcohol is selected from the group containing

methanol, blends of methanol and ethanol, and absolute ethanol.

16. The method of claim 14 wherein the alcohol is 3A ethanol.

17. A method of preparing substantially pure acyclovir by:

alkylating diacetyl-guanine with an alkylating agent to form diacetyl-acyclovir;

washing the diacetyl-acyclovir;

hydrolyzing the diacetyl-acyclovir in the presence of potassium hydroxide to

simultaneously form acyclovir potassium salt;

neutralizing the acyclovir potassium salt with an acid to form substantially purified

acyclovir; and

recovering the substantially purified acyclovir.

18. The method of claim 17 wherein the alkylating agent employed in the step of

alkylating diacetyl-guanine to form diacetyl-acyclovir is 2-oxa-l ,4-butanediol diacetate.

19. The method of claim 18 where the step of washing the diacetyl-acyclovir further

comprises washing the diacetyl-acyclovir with an alcohol.

20. The method of claim 19 wherein the alcohol is selected from a group containing

methanol, a blend of methanol and ethanol, and absolute ethanol.

21. The method of claim 19 wherein the alcohol is 3 A ethanol.

22. A method of preparing diacetyl-acyclovir comprising the steps of;

alkylating diacetyl-guanine with 2-oxa-l,4-butanediol diacetate to form diacetyl-

acyclovir; and

washing the diacetyl-acyclovir to remove impurities.

23. The method of claim 22 wherein the step of washing the diacetyl-acyclovir to remove

impurities further includes washing the diacetyl-acyclovir with an alcohol.

24. The method of claim 22 wherein the alcohol is 3 A ethanol.

25. A method of preparing a crystalline diacetyl-acyclovir comprising the steps of:

adding 2-oxa-l ,4 butanediol diacetate to a vessel;

adding methanesulfonic acid to the vessel;

adding diacetyl-guanine to the vessel;

adding toluene to the vessel to form a reaction mixture;

heating the reaction mixture;

collecting diacetyl-acyclovir; and

washing the diacetyl-acyclovir.

26. The method of claim 25 wherein the step of washing the diacetyl-acyclovir further comprises washing with an alcohol.

27. The method of claim 26 wherein the alcohol is selected from a group containing methanol, a blend of methanol and ethanol, and absolute ethanol.

28. The method of claim 26 wherein the alcohol is 3A ethanol.