\[ y'(x)=\frac {1}{2} i x^2 \left (-2 \sqrt {6 y(x)-x^3}+i\right ) \] ✓ Mathematica : cpu = 0.322259 (sec), leaf count = 67
\[\text {Solve}\left [12 i c_1+2 \sqrt {6 y(x)-x^3}+i \log \left (-x^3+6 y(x)+1\right )+2 i x^3=2 \tan ^{-1}\left (\sqrt {6 y(x)-x^3}\right ),y(x)\right ]\]
✓ Maple : cpu = 0.354 (sec), leaf count = 53
\[ \left \{ \ln \left ( {x}^{3}-6\,y \left ( x \right ) -1 \right ) -2\,i\sqrt {-{x}^{3}+6\,y \left ( x \right ) }+2\,i\arctan \left ( \sqrt {-{x}^{3}+6\,y \left ( x \right ) } \right ) +2\,{x}^{3}-{\it \_C1}=0 \right \} \]