>>8791107

https://patents.google.com/patent/WO2011161691A1/en

What is Claimed,

1. A direct method for preparation of quinine hydrochloride from cinchona bark comprising the following steps, i. Taking a known quantity of dried and pulverized Cinchona bark, mixed with quicklime in the ratio of 0.5: 0.9 and 6% caustic solution was added to this mixture.

ii. Blend obtained at step (i) was thoroughly mixed and kept aside for 6 to 12 hours after the specified time the blend was extracted using organic solvents at the ratio of 0.5:6 at 40 to 60 degree temperature for 2 to 4 hours preferably ,

iii. The second and third extraction was carried out using 0.5:4 blend and solvent ratio for 2 to 4 hours separately; the extracts were collected together and filtered through high flow bed. iv. The filtrate obtained at step (iii) was extracted with 5% hydrochloric acid and the mixture was stirred properly for 10 to 40 minutes, the solution was kept undisturbed until to get separate organic and aqueous layer, when two layers were completely separated out,

v. The aqueous layer obtained at step iv was collected and adjusted the pH 4 to 5 using 5% NaOH. Until to get maximum amount of precipitate was formed by addition of NaOH solution,

vi. The crude precipitate obtained at above step of various cinchona alkaloids was filtered and dried at 40° C using hot air, vii. To above resultant crude precipitate added hot distilled water ( 1 :5) slowly under constant stirring with 15% activated charcoal for 30 minutes at 65° C,

vii. The reaction mixture obtained at step vii allowed to filtered hot and the filtrate was continuously stirred until to reach a temperature of 30 C, followed by crystallization at ambient temperature, and dried at 40° C with hot air,

1. A direct method as claimed in claim 1 , wherein the organic solvents used are selected from toluene, methanol, ethanol, chloroform, acetone,more particularly toluene,

2. A direct method as claimed in claim 1 , wherein the Cinchona bark is mixed with quicklime in the ration of 0.5: 0.9 preferably 1 :0.4,

3. A direct method as claimed in claim 1, wherein the blend was thoroughly mixed and kept aside for 6 to 12 hours preferably 8 to 10 hr,

4. A direct method as claimed in above claims, wherein the blend was

extracted with Toluene at the ratio of 0.5:6 preferably 1 :5 at 40 to 60 degree temperature more preferably at 50° C for 2 to 4 hours preferably for 3 hrs,

1. A direct method as claimed in claim 1 , wherein the second and third

extraction was carried out using 0.5:4 more preferably 1 :3 blend and Toulene ratio for 2 to 4 hours preferably 3 hrs separately, followed by Alteration at high flew bed,

1. A direct method as claimed in claim 1 , wherein the filtrate was extracted with 5% hydrochloric acid and the mixture was stirred properly for 10 to 40 minutes preferably 30 minutes,

2. A direct method as claimed in claim 1 , wherein the two layers were

completely separated out, and the aqueous layer was collected and adjusted the pH 4 to 5 using 5% NaOH, precipitate was formed by adding NaOH solution, said crude precipitate cinchona alkaloids was filtered and dried using hot air, at 40° C ,

1. A direct method as claimed in above claims , wherein the crude precipitate and hot distilled water (1 :5) were added slowly under constant stirring using 15% activated charcoal for 30 minutes at 65° C,

2. A direct method as claimed in claim 1 and 9 wherein the s filtered hot and the filtrate was continuously stirred until to reach a temperature of 30° C the crystals were dried at 40° C with hot air,