FORM 2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2003 PROVISIONAL / COMPLETE SPECIFICATION (See section 10 and rule 13) 1 TITLE OF THE INVENTION : "PHARMACEUTICAL PROCESS AND COMPOUNDS PREPARED THEREBY" 2 APPLICANT (S) (a) NAME : CIPLA LIMITED (b) NATIONALITY : Indian (c) ADDRESS 289 Bellasis road, Mumbai Central, Mumbai 400 008, India 3 PREAMBLE TO THE DESCRIPTION PROVISIONAL The following specification describes the invention COMPLETE The following specification particularly describes the invention and the manner in which it is to be performed. 4. DESCRIPTION (Description shall start from next page) 5. CLAIMS (not applicable for provisional specification. Claims should start with the preamble - "I/we claim" on separate page) 6. DATE AND SIGNATURE (to be given at the end of last page of specification) 7. ABSTRACT OF THE INVENTION (to be given along with complete specification on separate page) WO 2004/063188 PCT/GB2004/000064 PHARMACEUTICAL PROCESS AND COMPOUNDS PREPARED THEREBY The present invention relates to an improved process for preparation of proton pump inhibitors, and to such proton pump inhibitors prepared thereby, compositions containing the same and uses thereof. Gastric proton pump inhibitors (PPIs) include substituted 2-(2-pyridylmemyl)-sulfinyl-lH- benzimidazoles, such as lansoprazole (2-[[[3-methyl-4-(2,2,2-trifluoro-ethoxy)-2- pyridinyl]methyl]sutfinyl] lH-benzimidazole), omeprazole (5-methoxy-2-[[(4-methoxy-3,5- dmethyl-2-pyirdyl)memyl]suhinyl]-lH-benzimidazole), pantoprazole (5-{difluoromethoxy)- 2-[[(3,4-dimethoxy-2-pyridiny) methyl] 1H-bezimidazale), and rabeprazole (2-[[[4- (3-methoxy-propoxy)3-metbyl-2-pyridmyl]methyl] sulfinyl]-1H –bezimidazole) These compounds can produce profound and sustained inhibition of gastric acid secretion, with responses of PPIs being more rapid compared with those seen with other anti-secretory drugs. PPIs work by inhibiting the production of stomach acid, by shutting down a system in the stomach known as proton pump, the full name of which is the hydrogen-potassium adenosine triphosphate enzyme system. PPIs are the drugs of choice in dyspepsia and peptic ulcers, and also Zollinger-Ellyson syndrome. In particular, in the treatment of peptic ulcers, the response rates of PPIs are superior to those seen with other drugs. The reported prior art synthesis of these substituted 2-(2-pyridylmethyl)-sulfinyl-lH-benzimidazoles generally involves an oxidation process of a sulfide compound to the corresponding sulfinyl compound. More particularly, prior art processes for the preparation of 2-(2-pyridylmemyl)-sulky-lH-benzimidazoles, generally involve the synthesis of the corresponding throatier compound, and its subsequent oxidation to the sulfinyl or sulfoxy compound, by various methods such as reaction with hydrogen peroxide over a vanadium compound catalyst, or reaction with peracids, peresters or ozone. There are several disadvantages associated with such known processes, primarily with respect to the nature of the thioether (or sulfide) compound being oxidized. WO 2004/063188 PCT/GB2004/000064 3 US Patent No. 4,628,098 to Nohara, et al. discloses a process for preparation of lansoprazole by oxidation of the sulphide precursor compound using peracids (m-chloro perbenzoic acid). US Patent No. 5,840,552 to Holt, et al. discloses a process for preparation of lansoprazole, wherein the sulphide precursor compound was selectively bio-oxidised to isolate the pharmaceuticalry active enantiomer or enantiomerically enriched corresponding sulfoxide form, using microorganisms or a microbial enzyme system. US Patent No. 5,374,730, to Slemon, et al. discloses a process for the preparation of omeprazole and lansoprazole, wherein amide analogues of the thioether compounds were readily oxidized to the corresponding sulfinyl compounds and the sulfinyl compounds were hydrolyzed in an alkaline medium to the corresponding carboxylic acid salts. The salts were subsequently decarboxylated to omeprazole or lansoprazole respectively. The disclosure refers to the advantages in relation to the purity of the final products, and the simplicity of the purification procedures. The amide compounds which were subjected to the oxidation step were crystalline solids, as opposed to oils, and as such could be readily purified to a high degree of purity by relatively simple precipitation, crystallization and washing procedures. The carboxylates and carboxylic acid salts which were formed in the subsequent synthetic step after oxidation were water soluble, whereas the final products, omeprazole and lansoprazole, are not water soluble. Accordingly, any un-reacted residues, and also other minor impurities in the final products, were simply removable by an aqueous washing procedure. Avoidance of significant discoloration of the product was the other advantage disclosed. US Patent No. 5,470,983 to Slemon, et al. discloses processes for producing lansoprazole from acetamide-sulfide compounds by a process of oxidation to form the amide sulfinyl compound, followed by alkaline hydrolysis to the sulfinyl carboxylate or salt, and decarboxylation. US Patent No. 5,502,195, to Slemon, et al. discloses a process for preparation of lansoprazole, wherein the acetamide sulphide was oxidized to the corresponding amide sulfinyl compound, which was subsequently hydrolysed in an alkaline medium to the carboxylic acid salt and then decarboxylated to form lansoprazole. WO 2004/063188 PCT/GB2004/000064 4- US Patent No. 6,423,846 to Moon, et al. discusses problems associated with prior art oxidation procedures for converting precursor compounds into lansoprazole, where many by products were formed and the yield of lansoprazole was low. EP Patent No. 134,400, GB Patent No. 2,134,523, US Patent No. 4,628,098 and Korean Patent No. 52,837 each disclose m-chloroperbenzoic acid as the oxidant. Spanish Patent Nos. 550,057; 540,147 and 539,793 respectively disclose sodium penodate, iodosomethylbenzene and iodosobenzene as the oxidant employed. These prior art processes were cited as being unviable because of the expensive oxidants used therein, the formation of many impurities and a low yield of the product in the range of about 60 to 80%. All these prior art process either use expensive catalysts or hazardous oxidizing reagents, such as peracids, which are not suitable for commercial manufacture of these compounds. Also over-oxidation of the thioether compound to the corresponding sulphone analogue is a common problem encountered with the prior art processes. to a sulfinyl compound of formula (I) There has thus been a long felt need for efficient and safe methods for the selective oxidation of a sulphide compound of formula (II) WO 2004/063188 PCT/GB2004/000064 wherein in both formulae (I) and (Q) R1 and R3 are selected from the group consisting of hydrogen, methyl or C1-4alkoxy, R2 is selected from the group consisting of substituted or unsubstantiated C1-4 alkoxy and R1 is selected from the group consisting of hydrogen or substituted or unsubstantiated C1-4alkoxy. The present invention now provides an efficient, safe and industrially feasible method for preparing various substituted 2-(2-pyridylme1hyl)-sulfinyl-lH-beri2drnida2oles. In particular, it is an aim of the present invention to provide an improved process for oxidation of (2-[[[3-methyM-(2,2,2-trifluoro-emoxy>2-pyridinyl]methyI]thio]lH- benzimtdazole to the corresponding (2-[[[3-methyl-4-(2,2,2-trifluoro-ethoxy)-2-pyridinyl]methyl]-sulfinyl]lH-benzimidazoIe (lansoprazole), preferably using an eco-friendly, inexpensive and readily available reagent. It is a further aim of the present invention is to provide an improved process for oxidation of ((5-methoxy-2-[[(4-memoxy-3,5-dlmethyl-2provide)methyl]-thio]-1H-benzimidazole, to the corresponding ((5-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyirdryl)methyl]-sulfinl]-IH- benzimidazole (omeprazole), preferably using an eco-friendly, inexpensive and readily available reagent. It is a further aim of the present invention is to provide an improved process for oxidation of ((5-difluoromethoxy)-2-[[(3,4-dlmethoxy-2-pyridinyl)methyl]thio]1H-benzimidazole, to the corresponding ((5