A greener approach for the synthesis of 1-N-methyl-(spiro[2.3′]oxindolespiro[3.2″]/spiro[2.3′]indan-1,3-dionespiro[2.2″])cyclopentanone-4-aryl pyrrolidines

Synthesis of a Novel Triheterocyclic Framework via 1,3‐Dipolar Cycloaddition of a Nitrile Oxide with Imidazo[2,1‐b][1,3]thiazole‐3(2H)‐ones

“…The presence of a singlet at δ 7.63 resulting from the benzylidene proton (H e ) indicates that the C═C of the benzylidene was not involved in the cycloaddition reaction. Furthermore, the absence of any singlet downfield of δ 6.5 would be assignable to the methine proton in 4b excluded the presence of the product 4b [6, 7].…”

“…The signal at δ 129.03 is assignable to the benzylidene carbon (C e ) (based on HMQC analysis). The absence of any signals in the range of δ 70–100, that would be assignable to the methine and spiro carbons in 4b , excluded the formation of 4b [6, 7]. In the 1 H‐ 13 C HMBC map of 3b , both H a and H b correlate with C c (123.73 ppm), and H b and benzylidene proton H e correlate with the carbonyl carbon C f (167.91 ppm).…”

Ninhydrin in synthesis of heterocyclic compounds

“…Some other dipolarophiles such as benzo[b]thiophene-1,1-dioxide, 202 3-arylmethylidene-4-chromanone, 203 monoarylmethylidene cyclopentanones, 204 3-phenyl-5-isoxazolone, 205 9-arylmethylidene fluorenes, 206 and (E)-3-aryl-1-(thiophen-2-yl)prop-2-en-1-ones, 207 were employed in the reaction with azomethine ylides to afford various spiro-pyrrolidines and pyrrolizidines 108-113, respectively ( Figure 2). Three-component regio-and product-selective domino protocols to synthesis a racemic mixture of novel cage diazapenta-and hexacyclic ring systems 115 and 116 through a 1,3-dipole generationcycloaddition-annulation sequence were reported (Scheme 28).…”

1,3‐Dipolar Cycloadditions of Stabilized Azomethine Ylides and Electrophilic Alkenes Mediated by a Recyclable TSIL·AgOAc Catalyst

“…[1,2] In addition, high stereospecificity, regio-, and diastereoselectivity are very frequently achieved due to the high control of the geometry of the dipole, as well as the preferential dipolarophile approach. For example, heterogeneous graphene oxide, [4] zinc oxide nanoparticles, [5] heterogeneous silver nanoparticle, [6] bentonite, [7] were used as a recyclable catalyst. [3] The 1,3-DCs performed with azomethine ylides generated through a decarboxylative route via iminium salts have been very frequently associated with green processes.…”