When the Strokes released their debut album, “Is This It,” in 2001, sporting seemingly shampoo-proof mops, seedy Chucks and an attitude that would usher in a new generation of cool, they were on top of the world. Their music, Manhattan hedonism embodied in every careless riff and lethargic bass line, made them critics' darlings and they couldn't have cared less. They were the new rebels, too unaffected to actually do anything save look really, really cool.

As frontman, Julian Casa­blancas was frenetic, effortless, collected. Two albums (one good, one not so much) and a three-year hiatus later, a lot has changed. On his debut solo album, “Phrazes for the Young,” Casablancas, former master of nonchalance, tries ­really hard to make you like him. His synth-y experimentalism seems more lacquered than layered, and his attempt at Oscar Wilde-like repartee only yields clunky platitudes.

On “Phrazes for the Young,” named after Wilde's pamphlet of epigrams, Phrases and Philosophies for the Use of the Young, Casablancas tries to rival the album's namesake in wit. The problem is, rather than thinking up brilliantly cutting remarks, Casablancas provides quippy clunkers like “It's nice to be important but it's more important to be nice,” from “4 Chords of the Apocalypse.”

Freed from the Strokes' garage-revival label, Casablancas shifts toward a more textured electronic sound. No shortage of digital doodads round off the characteristic roughness of Casablancas' voice, stripping him of the imperfect appeal his former growl provided. On “Phrazes,” Casablancas ventures toward the mainstream, earning mass appeal with radio-ready futuristic pop.

Though Casablancas really makes an effort to prove his value as a solo artist, he gets a bit mixed up along the way. He tries out electro-soul on “4 Chords of the Apocalypse,” Manhattan-meets-country kitsch on “Ludlow St.,” and Top 40 balladry on “Tourist.”

Casablancas shines on the charmingly airy “11th Dimension,” which floats along with jaunty danceabilty, and the album's best song is “Glass,” a hauntingly pretty, seriously dystopian tale. But on “Out of the Blue,” 31-year-old Casa­blancas sounds as though he's reflecting on a life coming to an end. The song takes Wilde's Phrases phrase “To be premature is to be perfect” a bit too literally.

Oscar Wilde was a strong ­believer in the supremacy of youth. Casablancas, in his ­attempts to emulate him, seems more like the elder aristocrats Wilde so often mocked. With the Strokes, Casablancas wrote about the New York lifestyle he knew and ended up with concise pop-rock gems. On “Phrazes for the Young,” he treads on high-minded ground and loses himself along the way.