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Synthesis of Chiral Ligands and Their Applications in Combinatorial Asymmetric Catalysis

Thesis Info

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Author

Zaman, Tariq

Program

PhD

Institute

National University of Sciences & Technology

City

Islamabad

Province

Islamabad

Country

Pakistan

Thesis Completing Year

2014

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/2721/1/2898S.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727481229

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Enhanced effectiveness of pharmaceuticals and agrochemicals is the most sought-after attribute in the field of enantioselective synthesis of chiral molecules where single enantiomer (R or S) is required, for which asymmetric catalysis is an attractive way. The synthesis of enantiomerically pure compounds in traditional way is difficult, costly and time-consuming process involving the running of long columns which create a lot of waste that causes water pollution. The selectivity of products are equally depends upon the catalyst and conditions of the reaction which makes the task harder for selecting and finding new catalytic system. Present work deals with the development of six families of chiral ligands libraries for rapid recognition of the best system, by using combinatorial chemistry, during hydrogenation of ketones, a starting material and as intermediate in a number of pharmaceutical processes. The ligands were both generated in situ and in pure form for the comparison of results and were obtained by simple condensation, providing one of the starting materials being chiral. Six families namely; bisimine, diamine, aminal, imine, iminophosphine and oxazoline were synthesized and tested in presence of Zn(II), Rh(I) and Rh(III) by using polymethylhydrosiloxane (PMHS), diphenylsilane and formic acid/sodium formate as hydrogen donor species for transfer hydrogenation during synthesis of selective chiral alcohols from achiral acetophenone. Overall 1566 catalytic systems were developed and subsequently tested and the yield and enantiomeric excesses were found by using 1H NMR and chiral High Performance Liquid Chromatography (HPLC) respectively with more than 90% ee and 99% conversion as the best result for imine and aminal ligands. It has been proven that ligands synthesized in-situ gave comparable and almost same results to purified version with best reproducibility.
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اُردو نعت میں’’ حسنِ کُن‘‘ کا اختصاص

اُردو نعت میں’’ حسنِ کُن‘‘ کا اختصاص
ڈاکٹر عارف حسین عارفؔ
نعت، کمالاتِ نبویﷺ کی تفسیر ہے۔یہ محض حضورﷺ کی منظوم توصیف کا نام ہی نہیں بلکہ حضور نبی کریمﷺ کے حقیقی کمالات کی ایسی پیشکش کا نام ہے جس سے ایمان میں تازگی اور بالیدگی اُسی وقت پیدا ہوتی ہے جب مدّاح کا دل رسول اللہﷺ کی محبت کے حقیقی جذبات سے سرشار ہو۔جذبۂ نعت دل میں محبتِ رسولﷺ کی شمع فروزاں کر دیتا ہے۔ اس سے جمالیاتی سرور کی تعبیر بھی حاصل ہوتی ہے۔ نعت توصیفِ مصطفیٰؐ کا وہ مستحسن انداز ہے جس میں الفاظ، زبان سے نہیں پلکوں سے ترتیب دیے جاتے ہیں۔ بقول راجا رشید محمود:
’’نعت سنتِ کبریا ہے ۔ قلم و زبان کا اس راہ پر قدم رکھناتلوار پر چلنا ہے ۔ اس فرض سے وہی شخص بطریقِ احسن عہدہ برآ ہو سکتا ہے جس کی نگاہ علم کے تمام شعبوں پر ہو، جو شریعت پر پوری طرح عامل ہو۔ جو رحمتِ عالمﷺ سے سچی محبت رکھتا ہو۔ جس شخص کوممدوحِ کبریا کی رفعتِ شان کا ادراک و احساس نہ ہو وہ نعت کیا لکھے گا،کیا سمجھے گا۔‘‘
نعت(ن ع ت) با لفتح(مؤنث)عربی زبان کا ایک مادہ ہے۔جو عام طور پر وصف کے مفہوم میں مستعمل ہے ۔ نعت کے معنی وصف کے ہیں۔ وصف میں جو کچھ کہا جائے اُ سے بھی نعت ہی سے تعبیر کیا جاتا ہے۔ وصف بیان کرنے والے کو ’ناعت‘ کہتے ہیں اور اس کی جمع’ نعات‘ ہے ۔ مضامین نعت کے مآخذ قرآن اور حدیث ہیں۔ قرآنِ مجید جس طرح اللہ تعالیٰ کی کتاب ہے اسی طرح وہ اسلامی ادب کی بھی پہلی کتاب ہے۔ اس میں رسولﷺ کے اوصافِ حمیدہ ملتے ہیں۔عربی کی مشہور لغت ’’المنجد‘‘ میں نعت کا مفہوم یوں بیان کیا گیا ہے:
’’نعتاً، تعریف کرنا،بیان کرنا، اچھی صفات دکھانا، اَنعَت،...

Significance of Philadelphia Chromosome in Chronic Myeloid Leukemia Patients of Anmol Hospital, Lahore, Pakistan

Background: Chronic myelogenous Leukemia is a form of cancer that was firstly recognizes to associate strongly with the chromosomal abnormality [t (9; 22) translocation] called Philadelphia chromosome. Objective: Philadelphia chromosome is a characteristic chromosomal marker that is associated with chronic myelogenous leukemia. Methods: More than one hundred patients of either sex were selected for the experiment. RNA was isolated from whole blood of patients so can use exclusively in RT-PCR. Results: Philadelphia chromosome in blood samples of patients with suspected diagnosis of CML was detected in 63% of patients. During our experimental studies on CML patients we do not encounter any complex translocation involving chromosome 8, 9 and 22.  Conclusions: Philadelphia chromosome is a precise cytogenetic marker the detection of which is significant for differential diagnosis and clinical organization of patients with clinical diagnosis of CML. It is of significant that Ph chromosome occurs in pre-leukemic stage and has great diagnostic significance.

Response to Tomato to Irrigation, Foliar Application of Calcium, Boron, Zinc and Post Harvest Calcium Treatments

Three experiments were conducted at Agriculture Research Institute (ARI) Tarnab, Peshawar, Pakistan during the year 2012-14 to study the “Response of tomato to irrigation, foliar application of calcium (Ca), boron (B), zinc (Zn) and post harvest calcium treatments”.In the first experiment, tomato plants were irrigated at 3, 6 and 9 days intervals. The nutrients (Calcium, Boron, and Zinc) content of tomato crop were investigated in relation to irrigation intervals and sampling time (0, 20, 40, 60 and 80 days after transplantation). The yield and quality attributes were evaluated in relation to irrigation intervals only. The highest leaf Ca content (1.19%), leaf Zn content (3.28 mg 100g-1 DW ), number of leaves (129.00 ), leaf area (56.88 cm2), number of flowers (6.33) and fruitcluster-1 (4.33), yield(21.66 t ha-1), fruit firmness (3.33 kg cm-2),lowest blossom end rot (4.80%) and fruit cracking (4.17%) were recorded in plants irrigated after 6 days, while the highest leaf boron content (4.07 mg 100g-1 DW), lowest TSS (1.72 °brix) and non reducing sugars (0.56%) were measured in plants with irrigation after every 3rd days. Root weight (164 g), reducing sugars (3.80%), and ascorbic acid content (13.67mg 100g-1) were recorded as maximum in plants with 9 days irrigation interval. The highest leaf Ca content (1.12%) was recorded in plants, when leaf samples were taken after 60 days, while leaf B and Zn content were recorded the highest i.e. 3.92 and 4.71 mg 100g-1 DW, respectively in tomato leaves, sampled after 80 days.In the second experiment, the effects of calcium, boron, and zinc foliar application on yield and fruit quality of tomato were studied. Calcium (0, 0.3, 0.6 and 0.9%), Boron (0, 0.25, 0.5%) and Zinc (0, 0.25, 0.5%) were applied as foliar spray, three times, 1st before flowering, 2nd at the time of fruit set and 3rd application was repeated 15 days after2nd application. Calcium application at 0.6% increased plant height (88.04 cm), number of primary (2.63) and secondary (7.15) branches, number of leaves plant-1 (182), leaf area (65.52 cm2), number of flowers cluster-1 (6.33), fruit cluster-1 (4.82), fruit plant-1 (66.15), yield (28.11 t ha-1 ) and decreased the flower drop (18.85%). Moreover, The highest number of flower cluster plant-1 (16.78), fruit weight (99.94 g), fruit firmness (2.99 kg cm-2), fruit Ca content (10.21 mg/100 DW), least TSS (3.38 °brix), blossom end rot (6.70%), fruit cracking (3.63%) and Zn content (2.08 mg/100 DW) were recorded at 0.9% Ca foliar application. In case of B levels, more plant height (88.14 cm), number of primary (2.61) and secondary (7.44) branches, number of leaves plant-1 (177), number of flowers cluster-1 (6.06), fruit cluster-1 (4.97), fruits plant-1 (67.78), yield (28.30 t ha-1) and reduced flower drop (17.86%), fruit cracking (4.44%) were recorded with foliar spray of B at 0.25%. Similarly, 0.5% B application significantly increased leaf area (62.33 cm2), number of flower cluster plant-1 (17.42), fruit weight (96.41 g), fruit firmness (2.86 kg cm-2), fruit Ca content (9.97 mg/100DW) and fruit B content (3.24 mg/100DW), lowest blossom end rot (11.44.0%), TSS (3.56 ° brix) and fruit Zn content (2.18 mg/100 DW). Comparing the means for Zn concentrations, maximum plant height (86.53 cm), number of primary (2.53) and secondary (6.42) branches, number of leaves plant-1 (167), leaf area (63.33 cm2), number of flowers cluster-1 (6.06), fruit cluster-1 (4.64), number of cluster plant-1 (16.64), fruit plant-1 (63.78), fruit weight (94.98 g), yield (28.80 t ha-1), ascorbic acid content (14.52 mg/ml), reducing sugar (3.07%),fruit B (3.27 mg/100 DW) and Zn (2.59 mg/100 DW) contents were higher while the incidence of blossom end rot (11.00%), fruit cracking (4.83%), non-reducing sugar content (1.11%) and fruit Ca content (8.88 mg/100DW) were lower with 0.5% foliar Zn application while the effect of Zn on flower drop was found non significant. By contrast, firmer fruit (2.82 kg cm-2) with lowest TSS (3.36 °brix) were recorded in plot, where Zn was not applied. In the 3rd experiment, the fruits of tomato were dipped in different calcium sources (calcium chloride, calcium gluconate, calcium lactate and calcium sulphate) at various concentration (0, 0.25, 0.50 and 0.75) and stored at low temperature (10± 2°C) and ambient temperature (32±2°C) and at relative humidity (60±5%) for 21 days. Higher fruit firmness (2.25 kg cm-2), percent acidity (0.34%), ascorbic acid content (9.90 mg 100g-1), non reducing sugars (1.58%), minimum physiological weight loss (20.18), TSS (4.99 °brix), reducing sugars (3.53%), sugar acid ratio (16.07), soft rot (18.49%) and black mold (16.63%) wererecorded in fruits stored at low temperature, while minimum cell membrane and cell wall ion leakage (41.58 and 22.64%, respectively) and green mold (20.58%) was recorded in fruits stored at ambient temperature. For calcium concentration, Ca at 0.75% significantly increased fruit calcium content (12.89 mg 100g-1), fruit firmness (2.60 kg cm-2), percent acidity (0.38%), ascorbic acid content (9.68 mg 100g-1), non reducing sugars (1.74%) and reduced physiological weight loss (14.33%), cell membrane and cell wall ion leakage (40.25 and 21,38%, respectively), TSS (5.03 °brix), sugar acid ratio (14.03), soft rot (11.02%) and green mold (13.73%) while reducing sugars (3.26%) and black mold (16.0%) were recordedminimum in tomatoes supplied with 0.5% calcium concentration. Regarding the means for calcium sources, more fruit firmness (2.82 kg cm-2), percent acidity (0.44%), ascorbic acid content (13.52 mg 100g-1), non reducing sugars (2.34%), minimum physiological weight loss (12.72%), cell membrane and cell wall ion leakage (37.50 and 19.06%, respectively), TSS (4.96 °brix), reducing sugars (3.10%), sugar acid ratio (11.49), soft rot (6.11%) and black mold (13.17%) and green mold (10.04%) were recorded in fruits treated with CaCl2. Therefore, it is concluded that 6 days irrigation interval resulted in better growth, more nutrient uptake, fruit quality and minimum physiological disorders (blossom end rot and fruit cracking). Calcium decline started after 60 days of growth, so foliar calcium should be applied before flowering and after fruit set to correct the calcium deficiency and control the Ca related physiological disorders like blossom end rot and fruit cracking. Foliar application on Ca, B, and Zn should be used alone or in combination to improve the fruit yield, minimize the physiological disorders and (blossom end rot and fruit cracking) and enhance fruit quality of tomato. Furthermore, CaCl2 at high concentration and low temperature should be used for maintaining quality of tomato fruits by reducing the post harvet diseases, increasing the fruit firmness, delaying ripening process, and prolonging the shelf life.