1. A process for preparation of Bicalutamide of formula (I),
comprising:
oxidizing of compound of formula (II),
with potassium permanganate in presence of water or with potassium permanganate in the presence of a mixture of water and water miscible solvent; and
isolating Bicalutamide of formula (I).
2. A process according to claim 1, wherein oxidizing is carried out at a temperature of 25-60\xb0 C.
3. A process according to claim 1, wherein oxidizing is carried out at a temperature of 25-45\xb0 C.
4. A process according to claim 1, wherein the water miscible solvent is selected from a nitrile, a ketone and an aliphatic acid.
5. A process according to claim 4, wherein the nitrile is selected from acetonitrile, propionitrile and benzonitrile.
6. A process according to claim 4, wherein the ketone is selected from acetone, methyl isobutyl ketone, methyl ethyl ketone and cyclohexanone.
7. A process according to claim 4, wherein the aliphatic acid is selected from acetic acid, propionic acid and butyric acid.
8. A process according to claim 1, wherein the water miscible organic solvent comprises acetonitrile.
9. A process according to claim 1, wherein the water miscible organic solvent comprises acetone.
10. A process according to claim 1, wherein the water miscible organic solvent comprises acetic acid.
11. A process according to claim 1, wherein the ratio of water to the water miscible organic solvent is between 1:1 and 1:4.
12. A process according to claim 1, wherein the ratio of water to the water miscible organic solvent is between 1:1 and 1:2.
13. A process according to claim 1, wherein potassium permanganate is in molar proportions of 1 to 3 equivalent per mole of compound of formula (II).
14. A process according to claim 1, wherein potassium permanganate is in molar proportions of 2 to 3 equivalent per mole of compound of formula (II).
15. A process according to claim 1, wherein isolated Bicalutamide of formula (I) employs acetonitrile.
16. A process according to claim 15, further comprising crystallizing Bicalutamide of formula (I) from a mixture of ethyl acetate and petroleum ether.
17. A process for preparation of Bicalutamide of formula (I)
comprising:
oxidizing a compound of formula (II),
with potassium permanganate in the presence of water or with potassium permanganate in the presence of a mixture of water and water miscible solvent; wherein the water miscible solvent comprises acetonitrile, propionitrile, benzonitrile, acetone, methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone, acetic acid, propionic acid, or butyric acid; and
isolating Bicalutamide of formula (I).
18. The process of claim 17, wherein the water miscible organic solvent comprises acetonitrile, acetone, or acetic acid.
19. The process of claim 18, wherein the water miscible organic solvent comprises acetonitrile.
20. The process of claim 17, wherein the ratio of water to the water miscible organic solvent is 1:1 to 1:4.
21. The process of claim 17, wherein potassium permanganate is in molar proportions of 1 to 3 equivalent per mole of compound of formula (II).
22. The process of claim 17, wherein isolating employs acetonitrile.
23. The process of claim 22, further comprising crystallizing Bicalutamide of formula (I) from a mixture of ethyl acetate and petroleum ether.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A photoconductive semiconductor switch, comprising:
a structure of nanopowder of a high band gap material, wherein the nanopowder is optically transparent,
wherein the nanopowder has a physical characteristic of formation from a sol-gel process.
2. The photoconductive semiconductor switch of claim 1, wherein the nanopowder is adapted to exhibit a lower electrical resistance when excited by light relative to an electrical resistance thereof when not exposed to the light.
3. The photoconductive semiconductor switch of claim 1, wherein the nanopowder comprises SiC.
4. The photoconductive semiconductor switch of claim 3, wherein a stoichiometric ratio of Si to C is 1:1.
5. The photoconductive semiconductor switch of claim 1, wherein the nanopowder comprises 6H-SiC.
6. The photoconductive semiconductor switch of claim 1, wherein the nanopowder includes a material selected from a group consisting of: 6H-SiC, 4H-SiC, and mixtures thereof.
7. The photoconductive semiconductor switch of claim 1, wherein the structure further comprises a dopant selected from a group consisting of nitrogen, vanadium and titanium.
8. The photoconductive semiconductor switch of claim 1, further comprising electrodes coupled to ends of the structure.
9. The photoconductive semiconductor switch of claim 1, where the structure has a volumetric size greater than about 1 mm3.
10. The photoconductive semiconductor switch of claim 1, wherein the structure is able to hold back an equivalent of at least about 50 kV per 1 mm3 of the structure.
11. The photoconductive semiconductor switch of claim 1, wherein the nanopowder has a mean particle diameter of less than about 1000 nanometers.
12. The photoconductive semiconductor switch of claim 1, wherein the nanopowder has a mean particle diameter of less than about 10 nanometers.
13. The photoconductive semiconductor switch of claim 1, wherein the structure has spatially varying properties.
14. The photoconductive semiconductor switch of claim 1, wherein the nanopowder has a physical characteristic of being formed, at least in part, by sintering the nanopowder in loose form.
15. The photoconductive semiconductor switch of claim 1, wherein the structure is substantially free of defects selected from a group consisting of: pipes, inclusions and impurities.
16. A method, comprising:
mixing a sol-gel precursor compound, a hydroxy benzene and an aldehyde in a solvent thereby creating a mixture;
causing the mixture to gel thereby forming a wet gel;
drying the wet gel to form a nanopowder; and
applying a thermal treatment to form a SiC nanopowder.
17. The method of claim 16, wherein the sol-gel precursor compound is a silicon alkoxide.
18. The method of claim 16, wherein the hydroxy benzene is selected from a group consisting of: resorcinol, catechol, hydroquinone, phloroglucinol and mixtures thereof.
19. The method of claim 16, wherein the aldehyde is selected from a group consisting of: formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, benzaldehyde and mixtures thereof.
20. The method of claim 16, wherein the solvent is water.
21. The method of claim 16, wherein the solvent is selected from a group consisting of: acetone, amyl acetate, dimethylsulfoxide, glycol, methanol, ethanol, propanol, isopropanol, and mixtures thereof.
22. The method of claim 16, further comprising adding at least one dopant to the mixture prior to causing the mixture to gel, wherein the at least one dopant is selected from a group consisting of: nitrogen, vanadium and titanium.
23. The method of claim 16, further comprising adding at least one catalyst to the mixture prior to causing the mixture to gel.
24. The method of claim 23, wherein the at least one catalyst is a base catalyst.
25. The method of claim 23, wherein the catalyst is ammonium hydroxide.
26. The method of claim 16, wherein causing the mixture to gel comprises adjusting a pH of the mixture andor heating the mixture at a gelation temperature for a gelation time.
27. The method of claim 16, further comprising washing the wet gel to remove dissolved nitrates prior to drying the wet gel.
28. The method of claim 16, wherein drying the wet gel comprises at least one of freeze drying, spray drying and supercritical drying.
29. The method of claim 16, wherein applying the thermal treatment includes heating the nanopowder at a temperature less than about 1100\xb0 C. in an atmosphere comprising at least hydrogen.
30. The method of claim 16, wherein applying the thermal treatment includes heating the nanopowder at a temperature between about 1100\xb0 C. and 1700\xb0 C. in an atmosphere comprising at least hydrogen.
31. The method of claim 16, further comprising heating the SiC nanopowder in air at a temperature less than about 450\xb0 C. to remove excess carbon.
32. The method of claim 16 further comprising sintering the SiC nanopowder.
33. The method of claim 32, wherein the sintering includes at least one of spark plasma sintering and hot isostatically pressing the SiC nanopowder in loose form.