Continuous flow solvent-free and catalyst-free mechanochemical production of rhodamine B dyes and their derivatives - Purohit, Mukesh; Shaikh, Tabrez Rafique; Kulkarni, Amol A. (Chemical Communications, 2025)
In this communication, we have described a simple and efficient, catalyst free and solvent-free protocol for the continuous flow synthesis of rhodamine B dyes developed from 3-diethyl amino phenol and phthalic anhydride. Nearly 95% conversion was achieved within 12 min using a jacketed single screw reactor. This method is further used for the synthesis of six derivatives with 70-84% yield, which can be compared to 85% yield from a 1-hour long batch synthesis involving a catalyst.

Continuous flow synthesis of metal nanowires: protocols, engineering aspects of scale-up and applications - Sonawane, Jayesh R.; Jundale, Rajashri; Kulkarni, Amol A. (Materials Horizons, 2025)
This review comprehensively covers the translation from batch to continuous flow synthesis of metal nanowires (i.e., silver, copper, gold, and platinum nanowires) and their diverse applications across various sectors. Metal nanowires have attracted significant attention owing to their versatility and feasibility for large-scale synthesis. The efficacy of flow chemistry in nanomaterial synthesis has been extensively demonstrated over the past few decades. Continuous flow synthesis offers scalability, high throughput screening, and robust and reproducible synthesis procedures, making it a promising technology. Silver nanowires, widely used in flexible electronics, transparent conductive films, and sensors, have benefited from advancements in continuous flow synthesis aimed at achieving high aspect ratios and uniform diameters, though challenges in preventing agglomeration during large-scale production remain. Copper nanowires, considered as a cost-effective alternative to silver nanowires for conductive materials, have benefited from continuous flow synthesis methods that minimize oxidation and enhance stability, yet scaling up these processes requires precise control of reducing environments and copper ion concentration. A critical evaluation of various metal nanowire ink formulations is conducted, aiming to identify formulations that exhibit superior properties with lower metal solid content. This study delves into the intricacies of continuous flow synthesis methods for metal nanowires, emphasizing the exploration of engineering considerations essential for the design of continuous flow reactors. Furthermore, challenges associated with large-scale synthesis are addressed, highlighting the process-related issues. This review comprehensively covers the translation from batch to continuous flow synthesis of metal nanowires (i.e., silver, copper, gold, and platinum nanowires) and their diverse applications across various sectors.

Continuous flow telescopic synthesis of 3-methoxy propiophenone by the grignard reaction - Wankhede, Pranali; Kulkarni, Amol A. (Organic Process Research & Development, 2025)
The synthesis of 3-methoxypropiophenone 1, a crucial intermediate in the production of the analgesic tapentadol hydrochloride, was investigated using a multistep continuous flow process. The approach is based on the Grignard reaction. A series of continuously stirred tank reactors (CSTRs) were employed: the first reactors facilitated the continuous generation of Grignard reagents 3, which then reacted with propionitrile in the next CSTR to yield 1. This was followed by quenching, neutralization, and phase separation, conducted under varying temperatures and residence times. When compared to a 50% yield from an optimized batch synthesis protocol, a continuous flow synthesis helped achieve an 84% yield of the desired product in a much shorter reaction time. A kinetic model was developed to predict the Grignard reagent formation and product yield, revealing that the mass transfer effect is insignificant at a higher stirring rate. The approach is highly scalable for the synthesis of pharmaceutical intermediates.
Keywords: batch and continuous reaction; flow chemistry; Grignard reaction; heterogeneous kinetics

Continuous flow β-zeolite catalysed regioselective alkylation of naphthols using alcohols for synthesis of peroxynaphthalen-2(1H)-one, Azidonaphthalen-2(1H)-one and Fluoronaphthalen-2(1H)-one derivatives - Londhe, Gokul; Bokade, Vijay; Gnanaprakasam, Boopathy (Asian Journal of Organic Chemistry, 2025)
Functionalized naphthols are prominent scaffolds in organic synthesis and materials chemistry. Herein, we demonstrated continuous flow alkylation of alpha- and beta-naphthols by using various primary and secondary benzylic alcohols in the presence of environmentally benign granular beta-zeolite as a reusable catalyst. For a variety of beta-naphthols, the respective alkylated products with good regioselectivity were obtained in high yields under mild reaction conditions. This protocol proceeded via the classical Friedel-Crafts type alkylation process and generated stable carbocations as intermediates. Applying this protocol, versatile naphthol derivatives have been synthesized using primary and secondary benzylic alcohols (50 and 44 examples in batch and continuous flow process, respectively), with good yields. Key advantages of this process includes rapid and efficient transformation, facilitates gram-scale synthesis, and generates water as the sole by-product. The most significant advantage is the continuous reusability of granular beta-zeolite, which further emphasizes the sustainability of the method. The application of alkylated naphthols for quaternary functionalization was demonstrated through peroxidation, azidation, and halogenation reactions under the continuous flow module, which yielded the respective peroxynaphthalen-2(1H)-one, azidonaphthalen-2(1H)-one and fluoronaphthalen2(1H)-one derivatives.
Keywords: continuous flow; Multigram Synthesis; Reusable beta-zeolite; Sustainable Appraoch; Transition metal free

Cyclopropane containing triterpenoids, cycloartenone, and cycloartenol: isolation, chemical transformations, and anticancer studies - Paul, Sayantan; Mandal, Kartik; Santra, Manas K.; Bhattacharya, Asish K. (ChemistrySelect, 2025)
Cycloartenone and cycloartenol, two plant-derived triterpenoids possessing cyclopropane ring were isolated from the latex of Artocarpus heterophyllus (jackfruit). Cycloartenol was chemically modified to synthesize dihydrocycloartenol via acetylation and deacetylation methodology followed by hydrogenation. Hydroxyl group present in the cycloartenol was also employed for the nitro benzoate formation. All the isolated and synthesized compounds were assayed against MCF7 breast cancer cell line for their anticancer properties.
Keywords: Anticancer studies; Artocarpus heterophyllus; Chemical transformations; Cycloartenol; Cycloartenone