Isatin (3a), isatin 3-carbohydrazone (4a), 5-spiro (isatin) 2-(N-acetyl hydrazino) 4-(N-acetyl)-∆2-1,3,4 oxadiazoline (5a), and 5-spiro (isatin) 2-hydrazino∆2-1,3,4 oxadiazoline (6a) had been synthesized from the unsubstituted oximinoacetanilide (2a). 4-Chlorooximinoacetanilide (2b), 5-chloroisatin (3b), 5-chloroisatin 3-carbohydrazone (4b) and 5-spiro (5-chloroisatin) 2-(N-acetyl hydrazino) 4...

Let $R$ be a commutative ring with identity. A proper submodule $N$ of an $R$-module $M$ is an n-submodule if $rmin N~(rin R, min M)$ with $rnotinsqrt{Ann_R(M)}$, then $min N$. A number of results concerning n-submodules are given. For example, we give other characterizations of n-submodules. Also various properties of n-submodules are considered.

We observe some new characterizations of $n$-presented modules. Using the concepts of $(n,0)$-injectivity and $(n,0)$-flatness of modules, we also present some characterizations of right $n$-coherent rings, right $n$-hereditary rings, and right $n$-regular rings.