Synthesis of 4-amino-5-allenylisoxazoles via gold(i)-catalysed propargyl aza-Claisen rearrangement

2021 ◽  
Vol 19 (6) ◽  
pp. 1358-1364
Author(s):  
Masato Tsuda ◽  
Taiki Morita ◽  
Shintaro Fukuhara ◽  
Hiroyuki Nakamura
Keyword(s):  
Claisen Rearrangement ◽  
High Yields ◽  
Cationic Gold

Propargyl aza-Claisen rearrangement of 4-propargylaminoisoxazoles 1 proceeded in the presence of cationic gold(i) catalysts to give 4-amino-5-allenylisoxazoles 2 in good to high yields.

scholarly journals Alkoxide-induced ring opening of bicyclic 2-vinylcyclobutanones: A convenient synthesis of 2-vinyl-substituted 3-cycloalkene-1-carboxylic acid esters

2012 ◽  
Vol 8 ◽  
pp. 650-657 ◽  
Author(s):  
Xiufang Ji ◽  
Zhiming Li ◽  
Quanrui Wang ◽  
Andreas Goeke
Keyword(s):  
Carboxylic Acid ◽  
Ring Opening ◽  
Claisen Rearrangement ◽  
Ring Cleavage ◽  
Unsaturated Ester ◽  
Supplementary Method ◽  
Convenient Synthesis ◽  
High Yields ◽  
Acid Esters

The fused 2-vinyl or 2-phenyl substituted cyclobutanones 4 undergo stereoselective ring openings by the action of alkoxide ions (t-BuO− or MeO−) to produce novel vicinally disubstituted cycloalkene derivatives 5 and 6 in moderate to high yields. The ring cleavage usually occurs with complete regioselectivity. The accessibility of γ,δ-unsaturated ester or acid derivatives makes this transformation a good supplementary method for the well-established Johnson–Claisen rearrangement.

Palladium-catalysed Claisen rearrangement of 6-allyloxypurines

2013 ◽  
Vol 67 (1) ◽  
Author(s):  
Petr Koukal ◽  
Hana Dvořáková ◽  
Dalimil Dvořák ◽  
Tomáš Tobrman
Keyword(s):  
Double Bond ◽  
Claisen Rearrangement ◽  
Mild Conditions ◽  
High Yields

Abstract6-Allyloxypurines readily undergo palladium-catalysed Claisen rearrangement under mild conditions affording N 1-substituted hypoxanthines. In contrast with the previously reported protocol, the Claisen rearrangement can be performed using Pd(PPh3)4 or Pd(dba)2/dppf in dry THF at 60°C. The reaction can accommodate variously substituted allyl fragments to position N 1 of the hypoxanthine skeleton with high yields. Retention of the double bond configuration during rearrangement was observed.

Synthesis of 1-alkoxy-1,2,3,4-tetra-hydrocarbazoles by mercury(II) mediated heterocyclization of 2-cyclohex-2′-enyl-N-alkylanilines

1996 ◽  
Vol 74 (8) ◽  
pp. 1592-1596 ◽  
Author(s):  
K. C. Majumdar ◽  
U. Das
Keyword(s):  
Key Words ◽  
Claisen Rearrangement ◽  
Supporting Evidence ◽  
Chemical Transformations ◽  
Key Words 1 ◽  
Acid Catalyzed ◽  
High Yields

The title compounds 3(a–i) were synthesized in high yields by the mercury(II) mediated heterocyclization of 2-cyclohex-2′-enyl-N-alkylanilines 2(a–g), which in turn were obtained by the acid-catalyzed amino Claisen rearrangement of 3-N-alkylanilinocyclohexenes 1(a–g). Additional supporting evidence for the structure of product 3 was obtained from chemical transformations. Key words: 1-alkoxy tetrahydrocarbazole, mercury(II) mediated heterocyclization, amino Claisen rearrangement, 3-N-methylanilinocyclohexene.

A route to large carbocycles using an alicyclic claisen rearrangement.

1982 ◽  
Vol 23 (52) ◽  
pp. 5455-5458
Author(s):  
A Cameron
Keyword(s):  
Claisen Rearrangement

A Simple Method for Preparing Fibrinogen

1966 ◽  
Vol 16 (01/02) ◽  
pp. 198-206 ◽  
Author(s):  
W Straughn ◽  
R. H Wagner
Keyword(s):  
Barium Sulfate ◽  
Caproic Acid ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Human Fibrinogen ◽  
Simple Method ◽  
High Yields ◽  
Marked Stability

SummaryA simple new procedure is reported for the isolation of canine, bovine, porcine, and human fibrinogen. Two molar β-alanine is used to precipitate fibrinogen from barium sulfate adsorbed plasma. The procedure is characterized by dependability and high yields. The material is 95% to 98% clottable protein but still contains impurities such as plasminogen and fibrin-stabilizing factor. Plasminogen may be removed by adsorption with charcoal. The fibrinogen preparations exhibit marked stability to freezing, lyophilization, and dialysis. Epsilon-amino-n-caproic acid and gamma-aminobutyric acid which were also studied have the property of precipitating proteins from plasma but lack the specificity for fibrinogen found with β-alanine.

A Novel Method for the Rapid Purification of Human and Rat Fibrin(OGEN) Degradation Products in High Yields

1979 ◽  
Author(s):  
W. Nieuwenhuizen ◽  
I. A. M. van Ruijven-Vermeer ◽  
F. Haverkate ◽  
G. Timan
Keyword(s):  
Degradation Products ◽  
Complete Separation ◽  
Purification Method ◽  
Amino Terminal ◽  
Novel Method ◽  
Rapid Purification ◽  
The One ◽  
High Yields ◽  
Size Heterogeneity ◽  
D Dimer

A novel method will be described for the preparation and purification of fibrin(ogen) degradation products in high yields. The high yields are due to two factors. on the one hand an improved preparation method in which the size heterogeneity of the degradation products D is strongly reduced by plasmin digestion at well-controlled calcium concentrations. At calcium concentrations of 2mM exclusively D fragments, M.W.= 93-000 (Dcate) were formed; in the presence of 1OmM EGTA only fragments M.W.= 80.000 (D EGTA) were formed as described. on the other hand a new purification method, which includes Sephadex G-200 filtration to purify the D:E complexes and separation of the D and E fragments by a 16 hrs. preparative isoelectric focussing. The latter step gives a complete separation of D (fragments) (pH = 6.5) and E fragments (at pH = 4.5) without any overlap, thus allowing a nearly 100% recovery in this step. The overall recoveries are around 75% of the theoretical values. These recoveries are superior to those of existing procedures. Moreover the conditions of this purification procedure are very mild and probably do not affect the native configuration of the products. Amino-terminal amino acids of human Dcate, D EGTA and D-dimer are identical i.e. val, asx and ser. in the ratgly, asx and ser were found. E 1% for rat Dcate=17-8 for rat D EGTA=16.2 and for rat D- dimer=l8.3. for the corresponding human fragments, these values were all 20.0 ± 0.2.

Studi Awal Geologi di Daerah Beruang Kanan Kabupaten Gunung Mas Propinsi Kalimantan Tengah

PROMINE ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 1-11
Author(s):  
Retno Anjarwati ◽  
Arifudin Idrus ◽  
Lucas Donny Setijadji
Keyword(s):  
Gold Mineralization ◽  
Volcanic Rocks ◽  
Gold Deposits ◽  
Central Kalimantan ◽  
Magmatic Arc ◽  
Tertiary Sediment ◽  
Copper Gold ◽  
Regional Tectonic ◽  
Mineralization Processes ◽  
High Yields

The regional tectonic conditions of the KSK Contract of Work are located in the mid-Tertiary magmatic arc (Carlile and Mitchell, 1994) which host a number of epithermal gold deposits (eg, Kelian, Indon, Muro) and significant prospects such as Muyup, Masupa Ria, Gunung Mas and Mirah. Copper-gold mineralization in the KSK Contract of Work is associated with a number of intrusions that have occupied the shallow-scale crust at the Mesozoic metamorphic intercellular junction to the south and continuously into the Lower Tertiary sediment toward the water. This intrusion is interpreted to be part of the Oligocene arc of Central Kalimantan (in Carlile and Mitchell 1994) Volcanic rocks and associated volcanoes are older than intrusions, possibly aged Cretaceous and exposed together with all three contacts (Carlile and Mitchell, 1994) some researchers contribute details about the geological and mineralogical background, and some papers for that are published for the Beruang Kanan region and beyond but no one can confirm the genesis type of the Beruang Kanan region The mineralization of the Beruang Kanan area is generally composed by high yields of epithermal sulphide mineralization. with Cu-Au mineralization This high epithermal sulphide deposition coats the upper part of the Cu-Au porphyry precipitate associated with mineralization processes that are generally controlled by the structure

Evaluation of germ plasm for resistant to Soybean mosaic virus (SMV)

2020 ◽  
Vol 21 (1) ◽  
pp. 6-9
Author(s):  
Wuye Ria Andayanie
Keyword(s):  
Abiotic Stress ◽  
Environmental Factors ◽  
Mosaic Virus ◽  
Polyclonal Antibody ◽  
Symptom Severity ◽  
Germ Plasm ◽  
Polyclonal Antibodies ◽  
Soybean Mosaic Virus ◽  
High Yield ◽  
High Yields

Soybean superior varieties with high yields and are resistant to abiotic stress have been largely released, although some varieties grown in the field are not resistant to SMV. In addition, the opportunity to obtain lines of hope as prospective varieties with high yield and resistance to SMV is very small. The method for evaluating soybean germplasm is based on serological observations of 98 accessions of leaf samples from SMV inoculation with T isolate. The evaluation results of 98 accessions based on visual observations showed 31 genotypes reacting very resistant or healthy to mild resistant category to SMV T isolate  with a percentage of symptom severity of 0 −30 %. Among 31 genotypes there are 2 genotypes (PI 200485; M8Grb 44; Mlg 3288) with the category of visually very resistant and resistant, respectively and  Mlg 3288  with the category of mild resistant.  They have a good agronomic appearance with a weight of 100 seeds (˃10 g) and react negatively with polyclonal antibodies to SMV, except Mlg 3288 reaction is not consistent, despite the weight of 100 seeds (˃ 10 g). Leaf samples from 98 accessions revealed various symptoms of SMV infection in the field. This diversity of symptoms is caused by susceptibility to accession, when infection occurs, and environmental factors. Keywords—: soybean; genotipe; Soybean mosaic virus (SMV); disease severity; polyclonal  antibody

Varieties of sweet potato and features of their cultivation technology

2020 ◽  
pp. 18-20
Author(s):  
Т.Э. Остонакулов ◽  
А.А. Шамсиев
Keyword(s):  
Sweet Potato ◽  
Sweet Potatoes ◽  
Marketable Yield ◽  
Early Maturity ◽  
Potato Varieties ◽  
Cultivation Technology ◽  
High Yields ◽  
Sprout Formation ◽  
Yield Formation

В 2017–2019 годах изучены сортообразцы сладкого картофеля на староорошаемых лугово-сероземных почвах Зарафшанской долины. Цель исследований – комплексная оценка сортообразцов батата в условиях Зарафшанской долины по скороспелости, росту, развитию, интенсивному размножению, формированию урожая, компактности клубней в гнезде, продуктивности, урожайности и лежкости клубней и выделение из них перспективных, а также разработка приемов агротехнологии получения высоких урожаев для данных условий. Почвы опытного участка характеризуются благоприятными агрофизическими и водными свойствами и низким содержанием гумуса, нитратного азота, подвижного фосфора и содержанием обменного калия от низкого до среднего. Сравнивали 18 сортообразцов батата. Выделенные сортообразцы изучали при ширине междурядий 70 и 90 см со схемой 70×25 и 90×20 см по 1, 2 и 3 растения в гнезде. Для получения рассады сортообразцов батата брали по 40 клубней и высаживали 20–22 февраля в пленочной теплице при температуре 15–18 °C, заделывая их на глубину 3–5 см. Влажность почвы поддерживали на уровне 65–70%. Через 7–10 дней после высадки почки начинают прорастать, а через 43–48 дней формируется рассада высотой 12–15 см, готовая для высадки в поле. Высадка рассады, как и других рассадных культур (томата, перца, баклажана) – по схеме 70×20–25 см во второй-третьей декаде апреля. Уход включал в себя междурядную обработку (культивация), прополку, борьбу с сорняками, подкормку, поливы. Уборка урожая – в конце сентября-начале октября с помощью картофелекопателя. В результате исследований выделились сорта по скороспелости, дружности формирования ростков, ускоренному размножению, продуктивности, компактности клубней в гнезде и с высоким товарным урожаем – Сочакинур, Хар-Бей и Япон. Возделывание этих сортообразцов по схеме 70×25 и 90×20 см способствует получению товарного урожая высокого качества не менее 43–48 т/га. In 2017–2019, studies were conducted on the study of varieties of sweet potatoes on old-irrigated meadow-gray-earth soils of the Zarafshan valley. The purpose of the research is a comprehensive assessment of sweet potato varieties in the conditions of the Zarafshan valley in terms of early maturity, growth, development, intensive reproduction, yield formation, compactness of tubers in the nest, productivity, yield and keeping quality of tubers and the selection of promising ones, as well as the development of methods of agricultural technology for obtaining high yields for given conditions. The soil is characterized by favorable agrophysical and water properties and low content of humus, nitrate nitrogen, mobile phosphorus and a low-average content of exchange potassium. Eighteen sweet potato varieties were compared. The selected variety samples were studied with a row spacing of 70 and 90 cm with a scheme of 70×25 and 90×20 cm for 1, 2 and 3 seedlings in the nest. To obtain seedlings of sweet potato varieties, 40 tubers were taken and planted on February 20–22 in a film greenhouse at a temperature of 15–18 °C, seeding to a depth of 3–5 cm, the soil moisture was maintained at 65–70%. 7–10 days after planting, the buds began to germinate, and after 43–48 days, seedlings were formed with a height of 12–15 cm, which is ready for planting in the field. Planting seedlings in the field is carried out, as well as other seedlings (tomato, pepper, eggplant) according to the scheme 70x20–25 cm in the second or third decade of April. Growing includes inter-row processing (cultivation), weeding, weed control, top dressing, watering. Harvesting in late September, early October with a potato digger. As a result of the research, varieties were identified in terms of early maturity, sprout formation, accelerated reproduction, productivity, compactness of tubers in the nest and ensuring a high marketable yield – Sochakinur, Xar-Bey, and Japon. The cultivation of these varieties according to the scheme 70×25 and 90×20 cm contributes to the production of a commodity crop at 43–48 t/ha with good qualities.

An Efficient Imine Photocyclization as an Alternative to the Pictet-Spengler Reaction for the Synthesis of AzaBenzannulated Perylenediimide Dyes

2020 ◽  
Author(s):  
Antoine Goujon ◽  
Lou Rocard ◽  
Thomas Cauchy ◽  
Piétrick Hudhomme
Keyword(s):  
Solar Cells ◽  
Visible Light ◽  
Organic Solar Cells ◽  
Reaction Sequence ◽  
Large Scope ◽  
High Yields

AzaBenzannulated PDI (AzaBPDI) dyes were synthesized in high yields via a new reaction sequence involving an imine condensation followed by visible light-induced photocyclization. The large scope and efficiency of this alternative to the Pictet-Spengler reaction is demonstrated, and allows the easy preparation of dimeric AzaBPDI as potential non-fullerene acceptors for organic solar cells.

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